Multilayered articles and method of manufacture thereof

This specification relates to a multilayer article and a manufacturing method. Specifically, the present specification relates to a multilayer sheet for IR absorption and a method for producing the same.

When the surface inside a vehicle, house or office building absorbs an excessive amount of sunlight, the temperature inside the room rises, the comfort of passengers and residents decreases, the deterioration of indoor materials is promoted, and large air conditioners The need for is increasing. Especially in automobiles, under the severe static exposure conditions found in automobiles parked in hot summer sunlight (especially in desert climate), the surface temperature inside a closed automobile can reach 100 ° C or higher, and the entire automobile can be seen. The amount of heat may rise to a high temperature.

<p> Increasing the cooling load on automobile air conditioners to improve thermal discomfort goes against the current trend in the automobile industry. Automobile engines are being miniaturized in order to reduce weight and improve fuel efficiency, and it is difficult to cope with the power consumption of large air conditioners. A recent concern in the industry and government is the role played by automotive air conditioners as a source of chlorofluorocarbons (CFCs) released into the atmosphere, and increased cooling loads lead to larger air conditioners, exacerbating this problem. Let me. Therefore, new technologies and passive design solutions that reduce the solar heat load in automobiles, houses, and office buildings are needed.</p>

<p> In the present specification, it is a multilayer sheet including a core layer containing a thermoplastic polymer and an IR absorber and a first cap layer containing a thermoplastic polymer and an electromagnetic ray absorber, and is a multilayer sheet of the first cap layer. Disclosed is a multilayer sheet in which the surface is arranged in close contact with the surface of the core layer.</p><p> In the present specification, a composition containing a thermoplastic polymer and an IR absorber is melt-blended to form a core layer, and a composition containing a thermoplastic polymer and an ultraviolet absorber is melt-blended to form a first cap layer. Also disclosed is a method for producing a multilayer sheet, which comprises forming and bonding the core layer and the first cap layer so that the first cap layer is arranged in close contact with the surface of the core layer.</p><p> The present specification also discloses a method for producing a multilayer sheet, which comprises coextruding a core layer containing a thermoplastic polymer and an IR absorber and a first cap layer containing a thermoplastic polymer and an ultraviolet absorber. To do.</p><p> The present specification also discloses articles including the above-mentioned multilayer sheet.</p>

In the present specification, the electromagnetic spectrum shows high light absorption in the ultraviolet (UV) region, high light absorption and high reflectance in the near infrared (IR) region, but high light transmittance and high in the visible region. A multilayer sheet showing reflectance is disclosed. The multilayer sheet contains a core layer containing a thermoplastic polymer and an IR absorber. In one embodiment, the surface of the core layer is placed in close contact with the surface of the first cap layer containing the thermoplastic polymer and the electromagnetic ray absorber. In another embodiment, the surface of the core layer is placed in close contact with the surface between the first cap layer and the second cap layer, each containing a thermoplastic polymer and an electromagnetic ray absorber. Multilayer sheets are generally attached in all applications (eg, buildings and automobiles) so that sunlight hits the cap layer before it hits the core layer. Multilayer sheets are preferably manufactured by coextrusion, which will be described later. In addition, all the ranges described in this specification include an upper limit and a lower limit, and they may be combined in any way.

The electromagnetic ray absorber may be one that absorbs any radiation from the electromagnetic spectrum. In one embodiment, the electromagnetic ray absorber is an ultraviolet (UV) absorber. In another embodiment, the electromagnetic ray absorber is an IR absorber capable of absorbing infrared rays. In yet another embodiment, the electromagnetic ray absorber is an absorber capable of absorbing infrared (IR) and ultraviolet (UV).

FIG. 1 is a schematic view in which the surface of the core layer is arranged between the surface of the first cap layer and the surface of the second cap layer, and FIG. 2 shows the surface of the core layer only on the surface of the first cap layer. It is the schematic which arranged in close contact. Both the core layer and the cap layer may be a single sheet of thermoplastic polymer or multiple sheets of thermoplastic polymer. From FIGS. 1 and 2, it can be seen that the thickness of the multilayer sheet means the thickness of the cap layer plus the thickness of the core layer.

As described above, both the core layer and the cap layer contain a thermoplastic resin. Thermoplastic polymers that can be used include oligomers, polymers, ionomers, dendrimers, copolymers (block copolymers, graft copolymers, stellate block copolymers, random copolymers, etc.), as well as combinations containing one or more of these polymers. Examples of suitable thermoplastic polymers that can be used for the core and cap layers are polyacetal, polyacrylic, polycarbonate, polystyrene, polyester, polyamide, polyamideimide, polyarylate, polyarylsulfone, polyethersulfone, polyphenylene sulfide, poly. Vinyl chloride, polysulfone, polyimide, polyetherimide, polytetrafluoroethylene, polyetherketone, polyetheretherketone, polyetherketoneketone, polybenzoxazole, polyoxaziazole, polybenzothiazinophenothiazine, polybenzothiazole, poly Pyrazinenoquinoxaline, polypyrromeritimide, polyquinoxalin, polybenzoimidazole, polyoxyindole, polyoxoisoindrin, polydioxoisoindrin, polytriazine, polypyridazine, polypiperazin, polypyridine, polypiperidin, polytriazole, polypyrazole, Polypyrrolidine, polycarbolane, polyoxabicyclononane, polydibenzofuran, polyphthalide, polyacetal, polyacid anhydride, polyvinyl ether, polyvinylthioether, polyvinyl alcohol, polyvinylketone, vinyl halide, polyvinylnitrile, polyvinyl ester, polysulfone, polysulfide , Polythioester, polysulfone, polysulfone amide, polyurea, polyphosphazene, polysilazane, etc., and there are combinations containing one or more of these thermoplastic polymers. The preferred thermoplastic polymer used for the core layer is polycarbonate or a copolymer of polycarbonate with polysiloxane. Preferred heat used for the cap layer

As described above, the core layer may be a single sheet of thermoplastic polymer or multiple sheets of thermoplastic polymer. The thermoplastic polymer preferably transmits light in the optical wavelength range of the electromagnetic spectrum. The core layer generally contains polycarbonate and IR absorbers. As used herein, the terms "polycarbonate", "polycarbonate composition" and "composition containing aromatic carbonate chain units" include compositions having structural units of formula (I) I.

<chemistry num="1"><img file="JP4137785B2_D0001.tif" /></chemistry>

In the formula, R¹About 60% or more of the total number of groups are aromatic organic groups, the rest of which are aliphatic groups, alicyclic groups or aromatic groups. Preferably R¹Is an aromatic organic group, more preferably a group of formula (II).

<chemistry num="2"><img file="JP4137785B2_D0002.tif" /></chemistry>

In the formula, A¹And A²Are monocyclic divalent aryl groups, respectively, and Y¹Is A¹And A²It is a bridging group that separates and from 0, 1 or 2 atoms. In an exemplary embodiment, A¹And A²Is separated by one atom. Y¹Specific examples of groups include -O-, -S-, -S (O)-, -S (O).₂-, -C (O)-, Methylene, Cyclomethylene, 2- [2.2.1]-Bicycloheptylidene, Ethylidene, Isopropylidene, Neopentylidene, Cyclohexylidene, Cyclopentadecylidene, Cyclododecylidene, There are Adamanthiriden and so on. In another embodiment, A¹And A²No atom intervenes between and, and a specific example is biphenyl. Bridge base Y¹May be a saturated hydrocarbon group such as methylene, cyclohexylidene or isopropylidene.

Polycarbonate can be produced by a Schotten-Bauman interface reaction of a carbonate precursor and a dihydroxy compound. Usually, an aqueous solution of a base such as sodium hydroxide, potassium hydroxide or calcium hydroxide is mixed with a water-immiscible organic solvent such as benzene, toluene, carbon disulfide or dichloromethane containing a dihydroxy compound. A phase transfer catalyst is commonly used to facilitate the reaction. The molecular weight modifier may be added to the reactant mixture alone or as a mixture. The branching agents described below can also be added alone or as a mixture.

Polycarbonate is A¹And A²Can be produced by an interfacial reaction of dihydroxy compounds separated by only one atom. The term "dihydroxy compound" as used herein includes, for example, the bisphenol compound of the following general formula (III).

<chemistry num="3"><img file="JP4137785B2_D0003.tif" /></chemistry>

In the formula, R^aAnd R^bRepresents hydrogen, halogen atom (preferably bromine) or monovalent hydrocarbon group independently, and p and q are each independently an integer of 0 to 4, and X^aRepresents one of the groups of equation (IV) below.

<chemistry num="4"><img file="JP4137785B2_D0004.tif" /></chemistry>

In the formula, R^cAnd R^dRepresent each independently a hydrogen atom or a monovalent linear or cyclic hydrocarbon group, R^eIs a divalent hydrocarbon group, oxygen or sulfur.

Specific examples of the type of bisphenol compound represented by the formula (III) include 1,1-bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, and 2,2-bis ( 4-Hydroxyphenyl) Propane (ie, Bisphenol A), 2,2-Bis (4-Hydroxyphenyl) Butane, 2,2-Bis (4-Hydroxyphenyl) Octane, 1,1-Bis (4-Hydroxyphenyl) Propane, 1,1-bis (4-hydroxyphenyl) n-butane, bis (4-hydroxyphenyl) phenylmethane, 2,2-bis (4-hydroxy-1-methylphenyl) propane, 1,1-bis ( Bis (hydroxyaryl) alkanes such as 4-hydroxy-t-butylphenyl) propane, 2,2-bis (4-hydroxy-3-bromophenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclopentane , 1,1-Bis (hydroxyaryl) cycloalkanes such as bis (4-hydroxyphenyl) cyclohexane, or combinations containing one or more of these bisphenol compounds.

Other bisphenol compounds represented by formula (III) have X as -O-, -S-, -SO- or -S (O).₂-There is something that is. Specific examples of such bisphenol compounds include bis (hydroxyaryl) ethers such as 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethylphenyl ether, 4,4'-. Dihydroxydiphenyl sulfide, bis (hydroxydiaryl) sulfides such as 4,4'-dihydroxy-3,3'-dimethyldiphenyl sulfide, 4,4'-dihydroxydiphenyl sulfoxide, 4,4'-dihydroxy-3,3'- Bis (hydroxydiaryl) sulfoxides such as dimethyldiphenylsulfoxide, bis (hydroxydiaryl) sulfoxides such as 4,4'-dihydroxydiphenylsulfone, 4,4'-dihydroxy-3,3'-dimethyldiphenylsulfone, and even these. There is a combination containing one or more of the above bisphenol compounds.

Other bisphenol compounds that can be used for polycondensation of polycarbonate include those represented by the formula (V).

<chemistry num="5"><img file="JP4137785B2_D0005.tif" /></chemistry>

In the formula, R^fIs a halogen atom of a hydrocarbon group having 1 to 10 carbon atoms or a halogen-substituted hydrocarbon group, and n is 0 to 4. If n is 2 or more, R^fMay be the same or different. Specific examples of the bisphenol compound represented by the formula (V) include resorcinol, substituted resorcinol compounds such as 5-methylresorcin, 5-ethylresorcin, 5-propylresorcin, 5-butylresorcin, 5-t-butylresorcin, 5-phenylresorcinol, 5-cumylresorcinol, etc., catechol, hydroquinone, substituted hydroquinone, eg 3-methylhydroquinone, 3-ethylhydroquinone, 3-propylhydroquinone, 3-butylhydroquinone, 3-t-butylhydroquinone, 3-phenyl There are combinations containing one or more of these bisphenol compounds, such as hydroquinone and 3-cumylhydroquinone.

2,2,2', 2'-tetrahydro-3,3,3', 3'-tetramethyl-1,1'-spirobi- [IH-indene] -6,6'represented by the formula (VI) -Bisphenol compounds such as diols can also be used.

<chemistry num="6"><img file="JP4137785B2_D0006.tif" /></chemistry>

Suitable polycarbonates further include those derived from bisphenols containing alkylcyclohexane units. Such polycarbonate has a structural unit of formula (VII).

<chemistry num="7"><img file="JP4137785B2_D0007.tif" /></chemistry>

In the formula, R^a~ R^dAre independently hydrogen and C₁-C₁₂Hydrocarbyl group or halogen, R^e~ RⁱAre independently hydrogen or C₁-C₁₂It is a hydrocarbyl group. As used herein, the term "hydrocarbyl" refers to residues containing only carbon and hydrogen. The residues may be aliphatic or aromatic, linear, cyclic, bicyclic, branched, saturated or unsaturated. The hydrocarbyl group may contain a heteroatom on or instead of the carbon and hydrogen atoms that make up the substituent. For example, when specifically mentioned as containing such a heteroatom, the hydrocarbyl group may contain a carbonyl group, an amino group, a hydroxyl group, etc., or the main chain of the hydrocarbyl group contains a heteroatom. May be good. Alkylcyclohexane-containing bisphenols, such as the reaction product of 2 mol of phenol and 1 mol of hydrogenated isophorone, are useful in the production of polycarbonate polymers with high glass transition temperatures and high thermal deformation temperatures. Such isophorone bisphenol-containing polycarbonate has a structural unit of formula (VIII).

<chemistry num="8"><img file="JP4137785B2_D0008.tif" /></chemistry>

In the formula, R^a~ R^dIs as defined above. Such isophorone bisphenol-based polymers include a non-alkylcyclohexane bisphenol-containing polycarbonate copolymer, a blend of an alkylcyclohexylbisphenol-containing polycarbonate and a non-alkylcyclohexylbisphenol polycarbonate, and are commercially available from Bayer under the trade name APEC. A preferred bisphenol compound is bisphenol A.

In one embodiment, the dihydroxy compound may be reacted with a hydroxyaryl-terminated poly (diorganosiloxane) to synthesize a polycarbonate-polysiloxane copolymer. Preferably, the polycarbonate-poly (diorganosiloxane) copolymer is prepared by introducing phosgene into a mixture of a dihydroxy compound such as BPA and a hydroxyaryl terminal poly (diorganosiloxane) under interfacial reaction conditions. Polymerization of the reactants can be facilitated by the use of tertiary amine catalysts or phase transfer catalysts.

The hydroxyaryl-terminated poly (diorganosiloxane) can be produced by a platinum-catalyzed addition reaction of a siloxane halide of the formula (IX) with an aliphatic unsaturated monohydric phenol.

<chemistry num="9"><img file="JP4137785B2_D0009.tif" /></chemistry>

In the formula, R⁴Is C_1-8Alkyl groups, haloalkyl groups such as trifluoropropyl and cyanoalkyl groups, and aryl groups such as phenyl, chlorophenyl and tolyl. R⁴Is preferably methyl, or a mixture of methyl and trifluoropropyl, or a mixture of methyl and phenyl.

Eugenol, 2-alkylphenol, 4-allyl-2-methylphenol, 4-allyl-2 are examples of aliphatic unsaturated monovalent phenols that can be used in the production of hydroxyaryl terminal poly (diorganosiloxane). -Phenylphenol, 4-allyl-2-bromophenol, 4-allyl-2-t-butoxyphenol, 4-phenyl-2-phenylphenol, 2-methyl-4-propylphenol, 2-allyl-4,6- Includes dimethylphenol, 2-allyl-4-bromo-6-methylphenol, 2-allyl-6-methoxy-4-methylphenol, 2-allyl-4,6-dimethylphenol, etc., and one or more of these. There are combinations.

Typical carbonate precursors include carbonyl chloride (phosgene), carbonyl halides such as carbonyl bromide, bishaloformates of divalent phenols such as bisphenol A and hydroquinone, and glycol bis such as ethylene glycol and neopentyl glycol. There are bishaloformates such as haloformates and diaryl carbonates such as diphenyl carbonates, di (tolyl) carbonates and di (naphthyl) carbonates. A preferred carbonate precursor for interfacial reactions is carbonyl chloride.

If the use of carbonate copolymers over homopolymers is preferred, polycarbonates obtained by polymerization of two or more dihydric phenols, or dihydric phenols and glycols, hydroxy-terminated or acid-terminated polyesters, dibasic acids, hydroxy acids or aliphatics. Copolymers with diacids can also be used. In general, useful aliphatic diacids have about 2-40 carbon atoms. The preferred aliphatic diacid is dodecanedioic acid.

Branched polycarbonates, as well as blends of linear and branched polycarbonates, can also be used for the core layer. Branched polycarbonate can be produced by adding a branching agent at the time of polymerization. Branching agents include polyfunctional organic compounds having three or more functional groups, and the functional groups include hydroxyl, carboxyl, anhydrous carboxyl, haloformyl, etc., and one or more of these branching agents can be used. Combinations including include are also included. Specific examples include trimellitic acid, trimeritic acid anhydride, trimellithyl chlorolide, tris-p-hydroxyphenylethane, isatin-bis-phenol, tris-phenol TC (ie 1,3,5-tris ((p-hydroxy)). Phenyl) isopropyl) benzene), tris-phenol PA (ie 4 (4 (1,1-bis (p-hydroxyphenyl) -ethyl) α, α-dimethylbenzyl) phenol), 4-chloroformylphthalic anhydride, There are combinations containing one or more of these branching agents, such as trimesic acid and benzophenone tetracarboxylic acid. The branching agent can be added at a level of about 0.05 to 4.0% by weight based on the total weight of the polycarbonate in a given layer.

In one embodiment, the polycarbonate can be produced by a melt polycondensation reaction of a dihydroxy compound and a carbonic acid diester. Specific examples of carbonic acid diesters that can be used in the production of polycarbonate include diphenyl carbonate, bis (2,4-dichlorophenyl) carbonate, bis (2,4,6-trichlorophenyl) carbonate, bis (2-cyanophenyl) carbonate, etc. Bis (o-nitrophenyl) carbonate, ditril carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (diphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate, dicyclohexyl carbonate, bis (o-methoxycarbonylphenyl) carbonate , Bis (o-ethoxycarbonylphenyl) carbonate, Bis (o-propoxycarbonylphenyl) carbonate, Bis-o-methoxyphenyl carbonate, Bis (o-butoxycarbonylphenyl) carbonate, Bis (isobutoxycarbonylphenyl) carbonate, o- Methoxycarbonylphenyl-o-ethoxycarbonylphenyl carbonate, bis-o- (t-butoxycarbonylphenyl) carbonate, o-ethylphenyl-o-methoxycarbonylphenyl carbonate, p- (t-butylphenyl) -o- (t-) Butoxycarbonylphenyl) carbonate, bis-methylsalityl carbonate, bis-ethylsalityl carbonate, bis-propylsalityl carbonate, bis-butylsalityl carbonate, bis-benzylsalicylate carbonate, bis-methyl-4-chlorosalicylate carbonate, etc. There is a combination containing one or more carbonic acid diesters. Preferred carbonate diesters are diphenyl carbonate or bis-methyl salicyl carbonate.

Preferred, the weight average molecular weight of polycarbonate has a molecular weight of about 3000-1000000 g / mol. In one embodiment, the polycarbonate has a molecular weight of about 10,000 to 100,000 g / mol. In another embodiment, the polycarbonate has a molecular weight of about 20000-50000 g / mol. In yet another embodiment, the polycarbonate has a molecular weight of about 25000-35000 g / mol.

Thermoplastic polymers are generally used in an amount of about 70-99.9% by weight based on the weight of the core layer. In one embodiment, the thermoplastic polymer is present in an amount of about 75-99.7% by weight based on the total weight of the core layer. In another embodiment, the thermoplastic polymer is present in an amount of about 80-99.5% by weight based on the total weight of the core layer. In yet another embodiment, the thermoplastic polymer is present in an amount of about 85-97% by weight based on the total weight of the core layer.

IR absorbers are generally metal borides or fine particles of boride, such as lanthanum boride (LaB).₆), Boride praseodymium (PrB)₆), Boride neodymium (NdB)₆), Boride cerium (CeB)₆), Boride gadolinium (GdB)₆), Terbium Boride (TbB)₆), Boride dysprosium (DyB)₆), Holmium boro (HoB)₆), Boride yttrium (YB)₆), Boride samarium (SmB)₆), Boride Europium (EuB)₆), Boride erbium (ErB)₆), Boride thulium (TmB)₆), Boride ytterbium (YbB)₆), Boride lutetium (LuB)₆), Strontium Heboate (SrB)₆), Calcium Boride (CaB)₆), Titanium Boride (TiB)₂), Zirconium Boride (ZrB)₂), Hafnium Boride (HfB)₂), Vanadium Boride (VB)₂), Boride tantalum (TaB)₂), Chromium boride (CrB and CrB₂), Molybdenum boride (MoB)₂, Mo₂B₅And MoB), Tungsten Boride (W)₂B₅) Etc., or a combination containing one or more of these borides.

The IR absorber prior to dispersion in polycarbonate is preferably in the form of nano-sized particles. The particle shape is not particularly limited, and may be spherical, amorphous, plate-shaped, whisker-shaped, or the like. Nanosized particles generally have an average major axis of about 200 nm or less. In one embodiment, the average major axis of the particles has an average major axis of about 150 nm or less. In another embodiment, the particles have an average major axis of about 100 nm or less. In yet another embodiment, the particles have an average major axis of about 75 nm or less. In yet another embodiment, the particles have an average major axis of about 50 nm or less. As mentioned above, nano-sized particles generally have an average major axis of about 200 nm or less. In one embodiment, more than 90% of the particles have an average major axis of about 200 nm or less. In another embodiment, more than 95% of the particles have an average major axis of about 200 nm or less. In yet another embodiment, over 99% of the particles have an average major axis of about 200 nm or less. Bimodal or higher particle size distributions may be used.

IR absorbers are generally about 0.001 ~ 2.0g / m²Used in the amount of. In one embodiment, the IR absorber is about 0.03 to 1.0 g / m.²Can be used in the amount of. In another embodiment, the IR absorber is about 0.05-0.75 g / m.²Can be used in the amount of. In yet another embodiment, the IR absorber is about 0.09 to 0.36 g / m.²Can be used in the amount of.

IR absorbers are generally used in an amount of about 0.02 to 3000 ppm based on the total weight of the core layer. In one embodiment, the IR absorber can be used in an amount of about 1-1500 ppm relative to the total weight of the core layer. In another embodiment, the IR absorber can be used in an amount of about 1.5-1250 ppm based on the total weight of the core layer. In yet another embodiment, the IR absorber can be used in an amount of about 2.5-600 ppm based on the total weight of the core layer, depending on the thickness of the sheet. In one embodiment, the core layer may include a heat stabilizer to compensate for the temperature rise caused by the interaction of IR light with the IR absorber. In addition, the addition of heat stabilizers protects the material during processing operations such as melt blending. In general, a polycarbonate layer containing an IR absorber can cause a temperature rise of about 20 ° C during exposure. The addition of heat stabilizers to the core layer improves the long-term aging properties of the multilayer sheet and prolongs its life cycle. In another embodiment, UV stabilizers may be added to the core layer if desired to prevent UV degradation. Suitable heat stabilizers include phosphite, phosphonite, phosphine, hindered amine, hydroxylamine, phenolic compounds, acryloyl-modified phenols, hydroperoxide degradants, benzofuranone derivatives, etc., or combinations containing one or more of these heat stabilizers. Suitable heat stabilizers on the market include IRGAPHOS 168, DOVERPHOS S-9228, ULTRANOX 641, and suitable UV stabilizers on the market are TINUVIN 329, TINUVIN 234, TINUVIN 350, TINUVIN 360 or UVINOL. There are 3030. If desired, an alicyclic epoxy polymer or an auxiliary stabilizer such as IRGANO X 1076 may be added to improve the thermal stability of the core layer. A preferred heat stabilizer is phosphite.

It is generally desirable to add the heat stabilizer in an amount of about 0.001 to 3% by weight based on the total weight of the core layer. In one embodiment, the heat stabilizer can be added in an amount of about 0.002 to 0.5% by weight based on the total weight of the core layer. In another embodiment, the heat stabilizer can be added in an amount of about 0.005 to 0.2% by weight based on the total weight of the core layer. In yet another embodiment, the heat stabilizer can be added in an amount of about 0.01 to 0.1% by weight based on the total weight of the core layer. When adding the auxiliary stabilizer, it is generally desirable to add it in an amount of about 0.001 to 2% by weight based on the total weight of the core layer.

In addition to heat stabilizers and UV stabilizers, other additives such as mold release agents, pigments, dyes, impact resistance improvers, lubricants, antioxidants, antimicrobial agents, flame retardants, visual effects agents, fibers, Antistatic agents, plasticizers, fillers such as carbon fiber, glass fiber, carbon nanotubes, etc., such as fumed silica, aerogel, carbon black, etc. may be added to both the core layer and the cap layer.

The thickness of the core layer is generally desirable to be about 0.5-30 mm. In one embodiment, the thickness of the core layer can be from about 0.75 to 25 mm. In another embodiment, the core layer thickness can be about 0.85-20 mm. In yet another embodiment, the core layer thickness can be about 1-15 mm.

As described above, the multilayer sheet may be one in which one cap layer is closely arranged on the core layer. Alternatively, the multilayer sheet may include two cap layers, one cap layer arranged in close contact with any surface of the core layer. The cap layer also generally contains a thermoplastic polymer. Suitable thermoplastic polymers are polycarbonate, copolyester carbonate or blends of polyester and polycarbonate. The polyester may be an alicyclic polyester, a polyarylate, or a combination of an alicyclic polyester and a polyarylate.

Alicyclic polyesters suitable for use in cap layers are characterized by optical transparency, excellent weather resistance, chemical resistance and low water absorption. It is also generally desirable for the alicyclic polyester to have good melt compatibility with the thermoplastic polymer used for the core layer. In one embodiment, it is preferable to use an alicyclic polyester having excellent melt compatibility with the polycarbonate used for the core layer. Alicyclic polyesters are generally produced by the reaction of a diol with a dibasic acid or derivative. Diols useful for the production of alicyclic polyester polymers used as high quality optical sheets are straight chain, branched or alicyclic alkane diols, preferably straight chain or branched alkane diols, which have a carbon number of atoms. It may be 2 to 12.

Suitable diols include ethylene glycol, propylene glycol such as 1,2- and 1,3-propylene glycol, butanediol such as 1,3- and 1,4-butanediol, diethylene glycol, 2,2-dimethyl-1. , 3-Propanediol, 2-ethyl-2-methyl-1,3-propanediol, 1,3- and 1,5-pentanediol, dipropylene glycol, 2-methyl-1,5-pentanediol, 1, There are 6-hexanediol, 1,4-cyclohexanedimethanol (particularly its cis and trans isomers), triethylene glycol, 1,10-decanediol or a combination containing one or more of these diols. Particularly preferred are dimethanol bicyclooctane, dimethanol decalin, alicyclic diols or their chemical equivalents, and in particular 1,4-cyclohexanedimethanol or its chemical equivalents. When 1,4-cyclohexanedimethanol is used as the diol component, it is generally preferred to use a mixture with a cis / trans isomer ratio of about 1: 4 to 4: 1. Within this range, it is generally desirable to use a cis / trans isomer ratio of about 1: 3.

Diacids useful in the production of alicyclic polyester polymers are aliphatic diacids, each including a carboxylic acid having two carboxyl groups attached to the saturated carbon of the saturated ring. Specific examples of suitable alicyclic acids include decahydronaphthalenedicarboxylic acid, norbornenedicarboxylic acid, and bicyclooctanedicarboxylic acid. Preferred alicyclic diacids are 1,4-cyclohexanedicarboxylic acid and trans-1,4-cyclohexanedicarboxylic acid. Linear aliphatic diacids are also useful, provided that the polyester has one or more alicyclic ring-containing monomers. Specific examples of linear aliphatic diacids include succinic acid, adipic acid, dimethylsuccinic acid and azelaic acid. Mixtures of diacids and diols can also be used in the production of alicyclic polyesters.

Cyclohexandicarboxylic acids and their chemical equivalents can be used, for example, in a suitable solvent (such as water or acetic acid) using a catalyst (such as a rodium carried on a suitable carrier such as carbon or alumina). It can be prepared by hydrogenating cyclic aromatic diacids such as isophthalic acid, terephthalic acid and naphthalene acid and their derivatives. It can also be produced using an inert liquid medium in which the acid is at least partially soluble under reaction conditions, and a palladium or ruthenium catalyst supported on carbon or silica.

Hydrogenation generally yields two or more isomers with carboxylic acid groups in the cis or trans positions. The cis isomer and the trans isomer can be separated by crystallization or distillation, and a solvent such as n-heptane may or may not be used for crystallization. The cis isomer is more miscible, but the trans isomer is particularly preferable because it has a higher melting temperature and crystallization temperature. A cis / trans isomer mixture can also be used, in which case the trans isomer accounts for about 75% by weight or more and the balance is cis isomer based on the total weight of the cis isomer and the trans isomer. Is preferable. When an isomer mixture or two or more diacids are used, a copolyester or a mixture of two polyesters can be used as an alicyclic polyester polymer.

Chemical equivalents, such as the esters of these diacids, can also be used in the production of alicyclic polyesters. Examples of suitable chemical equivalents of diacids include alkyl esters such as dialkyl esters, diaryl esters, anhydrides, acid chlorides, acid bromides, and combinations containing one or more of these chemical equivalents. is there. Preferred chemical equivalents are dialkyl esters of alicyclic diacids, and most preferred chemical equivalents are dimethyl esters of acids, especially dimethyl-trans-1,4-cyclohexanedicarboxylate.

Dimethyl-1,4-cyclohexanedicarboxylate can be obtained by ring hydrogenation of dimethyl terephthalate, and two isomers having carboxylic acid groups at the cis and trans positions are obtained. The isomers can be separated and trans isomers are particularly preferred. As mentioned above, isomer mixtures can also be used.

Polyester polymers are generally obtained by condensation or transesterification of a diol or a chemically equivalent component of a diol with a diacid or a chemically equivalent component of a diacid, and have a repeating unit of formula (X).

<chemistry num="10"><img file="JP4137785B2_D0010.tif" /></chemistry>

In the formula, R³Is a linear, branched or alicyclic alkanediol having 2 to 12 carbon atoms or an alkyl or cycloalkyl group having 2 to 12 carbon atoms which is a residue of a chemical equivalent thereof, and is R.⁴Is an alkyl or alicyclic group that is a decarboxyl residue derived from a diacid, but R³And R⁴At least one of the above is a cycloalkyl group.

A preferred alicyclic polyester is poly (1,4-cyclohexane-dimethanol-1,4-cyclohexanedicarboxylate) (PCCD) with repeating units of formula (XI).

<chemistry num="11"><img file="JP4137785B2_D0011.tif" /></chemistry>

This is R in equation (X)³Is the cyclohexane ring, R⁴Is a cyclohexane ring derived from cyclohexane dicarboxylate or a chemical equivalent thereof, selected from its cis isomer, trans isomer or a mixture of cis isomer and trans isomer.

Alicyclic polyesters are generally manufactured in the presence of suitable catalysts such as tetra (2-ethylhexyl) titanate in appropriate amounts (usually about 50-400 ppm titanium relative to the total weight of the final product). it can.

PCCD is generally completely mixed with polycarbonate. Polycarbonate-PCCD mixture is typically 5 cm, measured at 265 ° C, load 2.16 kg, residence time 4 minutes.³150 cm in 10 minutes (cc / 10 minutes or ml / 10 minutes) or more³It is desirable to have a melt volume rate (MVR) of 10 minutes or less. Within this range, measure at 265 ° C, load 2.16 kg, residence time 4 minutes, MVR of about 7 cc / 10 minutes or more, preferably about 9 cc / 10 minutes or more, more preferably about 10 cc / 10 minutes or more. It is generally desirable to have. Similarly, within the above range, it is desirable to have an MVR of about 125 cc / 10 minutes or less, preferably about 110 cc / 10 minutes or less, and more preferably about 100 cc / 10 minutes or less.

Other preferred alicyclic polyesters that can be mixed with polycarbonate are polyethylene terephthalate (PET), polybutylene terephthalate (PBT), poly (trimethylene terephthalate) (PTT), poly (cyclohexanedimethanol-co-ethylene terephthalate) (PETG). ), Poly (ethylene terephthalate) (PEN) and poly (butylene terephthalate) (PBN).

Another preferred polyester that can be mixed with other polymers is polyarylate. Polyarylate generally refers to a polyester consisting of an aromatic dicarboxylic acid and bisphenol. Polyarylate copolymers having a carbonate bond in addition to an aryl ester bond are called polyester-carbonates and can be suitably used in mixtures. The polyarylate can be produced by solution polymerization or melt polymerization of an aromatic dicarboxylic acid or an ester-forming derivative thereof and bisphenol or a derivative thereof.

In general, polyarylate preferably contains one or more diphenol residues along with one or more aromatic dicarboxylic acid residues. The preferred diphenol residue exemplified in formula (XII) is derived from the 1,3-dihydroxybenzene moiety (referred to herein as resorcinol or resorcinol moiety). The resorcinol or resorcinol moiety includes both unsubstituted 1,3-dihydroxybenzene and substituted 1,3-dihydroxybenzene.

<chemistry num="12"><img file="JP4137785B2_D0012.tif" /></chemistry>

In the formula, R is C_1-12At least one of alkyl or halogen, n is 0-3. Suitable dicarboxylic acid residues include monocyclic groups, preferably isophthalic acid, terephthalic acid or aromatic dicarboxylic acid residues derived from a mixture of isophthalic acid and terephthalic acid, or diphenyldicarboxylic acid, diphenyletherdicarboxylic acid and naphthalene. There are polycyclic groups such as -2,6-dicarboxylic acid, and aromatic dicarboxylic acid residues derived from combinations containing one or more of these polycyclic groups. A preferred polycyclic group is naphthalene-2,6-dicarboxylic acid.

Preferably, the aromatic dicarboxylic acid residue is derived from a mixture of isophthalic acid and / or terephthalic acid, as generally illustrated in formula (XIII).

<chemistry num="13"><img file="JP4137785B2_D0013.tif" /></chemistry>

Thus, in one embodiment, the polyarylate comprises the resorcinol allylate polyester represented by formula (XIV), while R and n are those defined by formula (XII) above.

<chemistry num="14"><img file="JP4137785B2_D0014.tif" /></chemistry>

In the formula, R is C_1-12It is at least one of alkyl or halogen, n is 0 to 3, and m is about 8 or more. It is preferable that R is hydrogen. Preferably, n is 0 and m is about 10-300. The molar ratio of isophthalic acid to terephthalic acid is about 0.25: 1 to 4.0: 1.

In another embodiment, the polyarylate comprises a heat-stable resorcinol allylate polyester having a polycyclic aromatic group represented by formula (XV).

<chemistry num="15"><img file="JP4137785B2_D0015.tif" /></chemistry>

In the formula, R is C_1-12It is at least one of alkyl or halogen, n is 0 to 3, and m is about 8 or more.

In another embodiment, the polyarylate is copolymerized to form a block copolyester carbonate containing a carbonate block and an arylate block. An example is a polymer with a structural unit of formula (XVI).

<chemistry num="16"><img file="JP4137785B2_D0016.tif" /></chemistry>

In the formula, R¹Are independent halogen or C_1-12Alkyl, m is greater than or equal to 1, p is about 0-3, R²Are independently divalent organic groups, and n is about 4 or more. n is preferably about 10 or more, more preferably about 20 or more, and most preferably about 30 to 150. m is preferably about 3 or more, more preferably about 10 or more, and most preferably about 20 to 200. In one embodiment, m is present in an amount of about 20-50.

It is generally desirable for the polyester to have a weight average molecular weight of about 500-1000000 g / mol. In one embodiment, the polyester has a weight average molecular weight of about 10,000 to 200,000 g / mol. In another embodiment, the polyester has a weight average molecular weight of about 30,000 to 150,000 g / mol. In yet another embodiment, the polyester has a weight average molecular weight of about 50,000 to 120,000 g / mol. An example of the molecular weight of polyester used for the cap layer is about 60,000 to 120,000 g / mol. These molecular weights are determined on the basis of polystyrene standards.

In one embodiment, it is desirable that the melt viscosity of the thermoplastic polymer used for the core layer matches the melt viscosity of the thermoplastic polymer used for the cap layer during molding of the multilayer sheet. In another embodiment, it is desirable that the melt viscosity of the thermoplastic polymer used for the cap layer be equal to the melt viscosity of the thermoplastic polymer used for the core layer when the two melts first come into contact during the molding of the multilayer sheet. In yet another embodiment, the melt viscosity of the thermoplastic polymer used for the cap layer is within 1% of the melt viscosity of the thermoplastic polymer used for the core layer when the two melts first contact during molding of the multilayer sheet. Is desirable. In yet another embodiment, the melt viscosity of the thermoplastic polymer used for the cap layer is within 5% of the melt viscosity of the thermoplastic polymer used for the core layer when the two melts first contact during molding of the multilayer sheet. It is desirable to have it. In yet another embodiment, the melt viscosity of the thermoplastic polymer used for the cap layer is within 10% of the melt viscosity of the thermoplastic polymer used for the core layer when the two melts first contact during molding of the multilayer sheet. It is desirable to have it. In yet another embodiment, the melt viscosity of the thermoplastic polymer used for the cap layer is within 20% of the melt viscosity of the thermoplastic polymer used for the core layer when the two melts first contact during molding of the multilayer sheet. It is desirable to have it.

Polyester and / or copolyester carbonate is generally used in an amount of about 70-99.9% by weight based on the weight of the cap layer. Within this range, an amount of about 75% by weight or more, preferably about 80% by weight or more, more preferably about 85% by weight or more can be used based on the weight of the cap layer. Within the above range, it is desirable to use an amount of about 98% by weight or more, preferably about 97% by weight or more, and more preferably about 95% by weight or more based on the weight of the cap layer.

The cap layer generally contains a suitable UV absorber. Suitable UV absorbers include benzophenones such as 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 4-dodecyloxy-2-hydroxybenzophenone, 2 -Hydroxy-4-octadeciloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2 , 2', 4,4'-tetrahydroxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,2'-dihydroxy-4,4 Bentriazoles such as'-dimethoxy-5-sulfobenzophenone, 2-hydroxy-4- (2-hydroxy-3-methylaryloxy) propoxybenzophenone, 2-hydroxy-4-chlorobenzophenone, for example 2,2'-( Hydroxy-5-methylphenyl) benzotriazole, 2,2'-(hydroxy-3', 5'-di-t-butylphenyl) benzotriazole, 2,2'-(hydroxy-Xt-butyl-5'-methyl) Other UV absorbers such as salicylates such as phenyl) benzotriazole, such as phenyl salicylate, carboxyphenyl salicylate, p-octylphenyl salicylate, strontium salicylate, pt-butylphenyl salicylate, methyl salicylate, dodecyl salicylate, eg resorcinol monobenzoate, 2'-Ethylhexyl-2-cyano-3-phenylcinnamate, 2-ethyl-hexyl-2-cyano-3,3-diphenylacrylate, ethyl-2-cyano-3,3-diphenylacrylate, [2, There are 2'-thiobis (4-t-octylphenolate)]-n-butylamine and the like, or combinations containing one or more of these UV absorbers. A preferred UV absorber for use in the cap layer is UVINUL 3030 commercially available from BASF.

UV absorbers are generally used in an amount of about 5-15% by weight based on the weight of the cap layer. In one embodiment, the UV absorber may be used in an amount of about 7-14% by weight based on the total weight of the cap layer. In yet another embodiment, the UV absorber may be used in an amount of about 8-12% by weight based on the total weight of the cap layer. In one embodiment, the UV absorber can be used in an amount of about 9-11% by weight based on the total weight of the cap layer.

It is generally desirable for the cap layer to have an average thickness of about 10-120 μm. In one embodiment, the thickness of the cap layer can be about 15-100 μm. In another embodiment, the thickness of the cap layer can be about 20-90 μm. In yet another embodiment, the thickness of the cap layer can be about 25-80 μm.

Multilayer sheets can generally be manufactured by laminating the sheets on a roll mill or roll stack after extrusion. Extrusion of each layer of the multilayer sheet can be carried out with a single-screw extruder or a twin-screw extruder. It is desirable to extrude the layers with a single-screw extruder and stack these layers on a roll mill. It is more desirable to co-extrude a plurality of layers with a single-screw extruder or a twin-screw extruder, and these layers may be appropriately laminated by a roll mill. The roll mill may be a two-roll mill or a three-roll mill, if desired. Coextrusion of multiple layers with a single-screw extruder is generally desirable for the production of multilayer sheets.

In one embodiment, upon extrusion of the core and cap layers, additives (eg, IR absorbers and UV absorbers) may be added to the extruder along with the thermoplastic polymer from the feed throat. In another embodiment, when the core layer and the cap layer are extruded, the additive may be added to the extruder in the form of a masterbatch. The thermoplastic polymer may be fed from the extruder feed throat and the masterbatch may be fed from the extruder feed throat or downstream of the feeder throat. In one embodiment, during the manufacture of the core layer, the thermoplastic polymer is fed to the feed throat of the single-screw extruder and the IR absorber is added downstream of the feed throat in the form of a masterbatch. In another embodiment, during the manufacture of the cap layer, the thermoplastic polymer is fed to the feed throat of the single-screw extruder and the UV absorber is added downstream of the feed throat in the form of a masterbatch.

In one embodiment, the desired compositions for the core layer and cap layer may be precompounded separately prior to coextrusion. In this case, the pre-compounded material is first melt-blended with a twin-screw extruder, single-screw extruder, Buss kneader, roll mill, etc., and then shaped into pellets, sheets, etc. suitable for subsequent coextrusion. .. Next, the pre-compounded core layer and cap layer compositions may be supplied to the respective extruders and co-extruded.

As mentioned above, it is desirable to coextrude the cap layer and the core layer. In one embodiment, as one of the co-extrusion methods for multilayer sheets, melt streams (extrudes) from various extruders are supplied to a feed block die, where the various melt streams merge before entering the die. In another embodiment, melt streams from various extruders are supplied to the multi-manifold internal confluence die. The various melt streams enter the die separately and merge just inside the final die orifice. In yet another embodiment, melt streams from various extruders are supplied to the multi-manifold external merging die. The external merging die has a completely separate manifold and a separate orifice for each melt stream, through which the melt streams flow out of the die separately and merge immediately after exiting the die outlet. Multiple layers stack just downstream of the die while still melting. A specific example of a die used in the manufacture of a multilayer sheet is a feed block die. In one embodiment, the extruders used for coextrusion of the core layer and the cap layer are uniaxial extruders, respectively. The co-extruded sheet may be calendared with a roll mill as appropriate. Multilayer sheets generally have a thickness of about 0.5-35 mm.

It is desirable that the multilayer sheet absorbs about 90% or more of the total IR incident on the sheet surface. In one embodiment, the multilayer sheet may absorb about 60% or more of the total IR incident on the sheet surface. In another embodiment, the multilayer sheet may absorb about 50% or more of the total IR incident on the sheet surface. In yet another embodiment, the multilayer sheet may absorb about 40% or more of the total IR incident on the sheet surface. In yet another embodiment, the multilayer sheet may absorb about 20% or more of the total IR incident on the sheet surface. In yet another embodiment, the multilayer sheet may absorb about 5% or more of the total IR incident on the sheet surface.

The multilayer sheet preferably absorbs about 90% or more of the total amount of UV incident on the sheet surface. In one embodiment, the multilayer sheet may absorb about 60% or more of the total amount of UV incident on the sheet surface. In another embodiment, the multilayer sheet may absorb about 50% or more of the total UV incident on the sheet surface. In yet another embodiment, the multilayer sheet may absorb about 40% or more of the total amount of UV incident on the sheet surface. In yet another embodiment, the multilayer sheet may absorb about 20% or more of the total amount of UV incident on the sheet surface. In yet another embodiment, the multilayer sheet may absorb about 5% or more of the total UV incident on the sheet surface.

It is generally desirable for the multilayer sheet to absorb as much electromagnetic light as possible in the UV and IR regions of the electromagnetic spectrum, but it is desirable to transmit light in the visible region of the electromagnetic spectrum. The visible region of the electromagnetic spectrum is generally a wavelength of about 400-700 nm. It is desirable that the light transmittance in the visible region of the sheet is about 20% or more. In one embodiment, it is desirable that the light transmittance in the visible region of the sheet is about 30% or more. In another embodiment, it is desirable that the light transmittance in the visible region of the sheet is about 40% or more. In yet another embodiment, it is desirable that the light transmittance in the visible region of the sheet is about 50% or more.

It is also desirable that the multi-layer sheet has a haze of about 5% or less. In one embodiment, the haze may be about 2% or less. In another embodiment, the haze may be about 1.8% or less. In another embodiment, the haze may be about 1.6% or less.

When the resulting multilayer sheet is in the form of a multi-wall sheet, it is generally desirable that the haze is less than about 25%. In one embodiment, the haze may be about 20% or less. In another embodiment, the haze may be about 15% or less. In another embodiment, the haze may be about 10% or less.

The multilayer sheet thus produced can be suitably used in automobiles, houses, office buildings and other fields where heat generation due to infrared exposure is inappropriate. In one embodiment, the sheet can be used as a roofing material or a transparent film material after being coextruded as a multi-walled sheet with air passages between the walls, as shown in FIG. FIG. 3 is a schematic view of a multi-walled seat, the upper and lower seats are separated by brackets and have air pockets between the brackets. The sheet thickness is also shown in FIG. 3, and the sheet thickness includes the bracket part in addition to each multi-layer sheet. Brackets can also be made from the thermoplastic polymers described above. In one embodiment, the bracket can be made from polycarbonate, polyester or polyester carbonate-polyester.

The multilayer sheet thus formed may be further subjected to additional processing such as thermoforming, vacuum forming, blow molding, shaping, etc. in order to produce materials of various shapes and dimensions.

The following examples illustrate compositions and methods of making some of the various embodiments of a multilayer sheet using different materials and equipment, but these examples are for illustration purposes only and are limited. It's not something.

<u style="single">Comparative example</u> This example was performed in combination with Example 1 below in order to demonstrate the advantages of blending the IR absorber in the core layer as compared with the case where the IR absorber was blended in the cap layer. These examples include a cap layer (UV absorber) on the surface of the core layer (containing an IR absorber) so that when the multilayer sheet is exposed to sunlight, the sunlight contacts the cap layer before the core layer. It was also done to demonstrate the advantages of providing (contains). In these examples, the cap layer (LaB) is on top of the polycarbonate layer.₆A 3 mm multilayer sheet provided with (consisting of polycarbonate containing an IR absorber) and a UV absorber) was compared with a multilayer sheet provided with a UV absorber-containing cap layer on an IR absorber-containing core layer. In a comparative example, an IR absorber (LaB)₆) Was added to the cap layer, and in Example 1 described later, an IR absorber (LaB) was described.₆) Is incorporated into the core layer to describe the beneficial results obtained.

The thickness of the cap layer was about 60 μm, but the thickness of the cap layer fluctuated between about 50 and 80 μm due to the variation in thickness. Details of the composition and composition of the cap layer and the core layer were as follows.

<u style="single">LaB in the cap layer</u>_{<u style="single">6</u>} Polycarbonate was used as the thermoplastic polymer for both the cap layer and the core layer. The polycarbonate was a linear bisphenol A polycarbonate with a weight average molecular weight of 30,000 g / mol.

Cap layer is 0.18g / m²LaB₆, 10% Tinuvin 234 and 0.1% Irgafos 168, with the balance being bisphenol A polycarbonate. LaB₆LaB in linear bisphenol A polycarbonate with a weight average molecular weight of 30,000 g / mol₆Obtained from a masterbatch containing 0.25 wt%. The above components were pre-compounded with a twin-screw extruder to obtain a cap layer pre-compound.

The core layer was first precompounded in a twin-screw extruder. The core layer contains 99.75% by weight of linear bisphenol A polycarbonate with a weight average molecular weight of 30,000 g / mol, 0.1% by weight of pentaerythritol tetrastearate, 0.1% by weight of Tinuvin 234, and 0.05% by weight of Irgafos 168. The pre-compounds of the core layer and the cap layer were co-extruded as follows to obtain a multilayer sheet.

The extruder used to extrude the core layer was a 133 mm Werner and Pfleiderer ZSK extruder (biaxial extruder). The barrel temperature was set to 200 to 280 ° C, respectively. The die temperature was 250 ° C and the screw speed was 85 rpm. The five barrel temperatures from the feed throat to the die were 250, 260, 260, 270 and 280 ° C, respectively. The zone temperature of the extruder (Macgi, single-screw extruder with a barrel diameter of 45 mm) used to manufacture the cap layer was set to 200 to 280 ° C, and the screw speed was set to 58 rpm. For each single-screw extruder, six barrels were used with barrel temperatures set to 245, 255, 230, 230, 270 and 280 ° C, respectively. The barrel temperatures are in the order from the supply throat of the single-screw extruder toward the feed block, respectively. Table 1 shows some properties of the core layer.

For extrusion of the core layer and cap layer, pre-compound pellets of the essential composition were fed from the feed throat to the extruder. The extrudes from each extruder were fed to a feed block die to form a coextruded multilayer sheet. Light transmittance and haze were measured according to ASTM D1003, and Lab chromaticity was measured according to CIE Lab DIN 5033. The results are shown in Table 1 below.

<tables num="1"><img file="JP4137785B2_D0017.tif" /></tables>

From Table 1, it can be seen that there is a wide variation in light transmittance (LT) of about 53.4 to 63%. Similarly, when an IR absorber is added to the cap layer, the haze of the multilayer sheet exceeds 7%, resulting in a large variation in the level of sunlight transmittance.

<u style="single">Example 1</u> As described above, in this embodiment, LaB is applied to the core layer.₆Shows the effect when The amount of LaB shown in sample 1 in Table 1₆Was co-extruded together with the UV cap layer in a three-layer multilayer sheet containing the above in the core layer. The sheet contains two cap layers and one core layer. The core layer was located between the two cap layers.

The cap layer of the three-layer sheet was made in the form of a precompound containing 10% by weight of UV absorber (Tinuvin 234), 0.1% by weight of heat stabilizer (Irgafos 168) and 89.9% of linear bisphenol A polycarbonate.

The core layer was pre-compounded by supplying and mixing the following product logistics. 0.032% by weight LaB₆LaB consisting of 0.05 wt% Irgafos 168, 99.918 wt% linear polycarbonate with a weight average molecular weight of 30,000 to 31000 g / mol₆Masterbatch 16% by weight. Second, a UV concentrate of 5% by weight consisting of 97.5% by weight of linear polycarbonate with an average molecular weight of 30000g / mol, 2% by weight of Tinuvin 234 and 0.1% by weight of Irgafos 168. The rest consisted of 79% by weight of linear polycarbonate with a weight average molecular weight of 30,000 g / mol.

Next, as described in detail in the comparative example, the precompound was supplied to each extruder to produce a multilayer sheet. The results are shown in Tables 2 and 3. Table 2 shows LaB₆Shows some properties of a multi-layer sheet in which is compounded in the core layer. Table 3 shows the results obtained with a multilayer sheet containing a UV absorber in the cap layer and an IR absorber in the core layer. In either case, the irradiation radiation first hits the cap layer.

<tables num="2"><img file="JP4137785B2_D0018.tif" /></tables>

<tables num="3"><img file="JP4137785B2_D0019.tif" /></tables>

From Table 1 (Comparative Examples) and Table 3 (Examples of the present invention), IR absorbers (LaB)₆) Is blended in the cap layer, it can be seen that the light transmittance (LT%) and haze vary greatly as compared with the multilayer sheet in which the IR absorber is blended in the core layer. It can also be seen from Table 3 that the variations in light transmittance, haze and chromaticity are smaller than those in the sample in Table 1. Since it is desirable that the haze is as low as possible, dispersing the IR absorber in the core layer gives a better product than the product in which the IR absorber is blended in the cap layer. Figure 4 shows LaB₆Multi-layer sheet and LaB₆The photograph of the object through the two kinds of multi-layer sheets in which the above is mixed in the cap layer is shown. From this figure, LaB₆The object looks clear even through a multi-layer sheet containing the above in the core layer, but LaB₆It can be clearly seen that it is almost invisible when it is passed through a multi-layer sheet containing the above. LaB₆You can clearly see the color unevenness when using the cap layer.

Other observations were made in this test. As described above, a variation in the thickness of the cap layer of ± 20 μm was observed. Polycarbonate 1m as a target amount to make IR absorption reasonable²0.18g of LaB per₆It was used. When this amount of IR absorber is added to the 60 μm cap layer instead of the 3-6 mm core layer, the concentration in the cap layer becomes very high, resulting in unacceptable levels of haze in the multilayer sheet. In addition, a UV protective coating or UV absorber containing cap layer is used on the multilayer sheet to protect the polycarbonate from UV aging. A certain concentration of UV absorber is required to bring the UV protection of the PC to an acceptable level. By making the cap layer thicker, for example, by using a cap layer having a thickness of 500 μm (0.5 mm), it is conceivable to reduce the problem of the variation in the thickness of the cap layer and the accompanying variation in the transmittance. However, not only is there a problem in manufacturing the cap layer, but also a high concentration of UV absorber is required for the entire cap layer, which increases the cost of the entire multilayer sheet.

<u style="single">Example 2</u> This example was carried out to examine the effect of thermoforming of a multilayer sheet on light transmittance, solar factor, shading coefficient and haze. LaB₆Concentration is 0.09g / m²And 0.18g / m²Two types of 3 mm multilayer sheets were thermoformed on the device shown in FIG. Lab chromaticity was measured according to CIE Lab DIN 5033, solar transmittance was measured according to ISO 9050, and haze and light transmittance were measured according to ASTM D1003. When the multilayer sheet is thermoformed on the device shown in FIG. 5, the sheet shows a variation in thickness of 1.15 to 2.4 mm. The variation in the thickness of the cap layer is about 23 to 48 μm.

<u style="single">Example 3</u> In this example, LaB in the polycarbonate core layer when the thickness of the core layer is 1 mm₆The preferred range of the above will be described. Various amounts of LaB₆Polycarbonate samples containing Irgaphos 168 at 500 ppm were prepared on a 25 mm Werner and Pfleiderer twin-screw extruder. A 1 mm flat plate was injection molded with an Engel 75T device.

Infrared transmittance was measured with Hitachi U3410 UV-VIS-NIR. The average IR transmittance (IR-T%) from 780 to 1400 nm was calculated. Irradiation in this wavelength range is the largest cause of heat generation. The results are shown in Table 4.

<tables num="4"><img file="JP4137785B2_D0020.tif" /></tables>

From this data, when the core layer thickness is 1 mm, the polycarbonate core layer has more than 0.77% of LaB.₆It can be seen that no further IR absorption effect can be obtained by adding.

From the above examples, it can be seen that it is advantageous to use a multilayer sheet in which an IR absorber is blended in the core layer. This protects the IR absorber from atmospheric moisture and extends the life of the multilayer sheet. Furthermore, from the above results, it can be seen that there is a synergistic effect in combining the cap layer containing the UV absorber and the core layer containing the IR absorber. From the above results, it is clear that in the above configuration, the transparency is improved, the haze is low, and the color is excellent. Therefore, these multilayer sheets can be effectively used in automobiles, houses, and office buildings.

Although the present invention has been described with reference to exemplary embodiments, those skilled in the art will appreciate that various modifications can be made without departing from the technical scope of the invention and that its components can be replaced with equivalents. It will be self-evident. Numerous modifications can be made to adapt the individual circumstances or materials to the teachings of the invention without departing from the technical scope of the invention. Therefore, the present invention is not limited to the individual embodiments disclosed as the best embodiment thereof, and the present invention includes all embodiments belonging to the scope of claims.

<figref num="1">It is the schematic of the core layer arranged between the two cap layers which concerns on this invention.</figref><figref num="2">It is the schematic of the core layer arranged in close contact with a single cap layer.</figref><figref num="3">FIG. 5 is a schematic view of a multi-walled seat in which each seat is separated by brackets and has air pockets between the brackets.</figref><figref num="4">LaB₆A multi-layer sheet containing the above in the core layer and LaB₆It is a photograph of an object seen through two types of multi-layer sheets, which are multi-layer sheets containing the above in the cap layer.</figref><figref num="5">It is a figure of the device which performed the thermoforming experiment.</figref>