Preparation of polyolefin based thermoplastic elastomers

The invention relates to a polyolefin-based thermoplastic elastomer which can be prepared without a separate vulcanization step and which has a dispersed phase polyacrylate which is obtained by polymerizing acrylate within the polyolefin matrix.

Thermoplastic elastomers are polymers that possess the good machining properties of thermoplastics but have the same physical properties as vulcanized rubber. This combination of properties can be obtained by the material containing both soft and elastic segments, with low t, and hardening of any crystallizable segments, with high glass temperature or high melting point. The hardened and soft segments must be thermodynamically incompatible with each other, so that they form separate phases. Thermoplastic elastomers do not require a separate vulcanization step, as opposed to conventional rubber, and can be processed into various articles with the processing methods normally used for thermoplastics and which may be difficult or impossible to use for conventional rubber such as, for example. extrusion, injection molding and blow molding. In contrast to rubber, thermoplastic elastomers can also be reworked if necessary, e.g. when consuming materials during processing.

Thermoplastic elastomers can be divided into two main groups, block copolymers and thermoplastic elastomer blends. A well-known example of a block copolymer which is a thermoplastic elastomer is anionically polymerized block copolymer of styrene and butadiene (SBS) and hydrogenated form thereof (SEBS). In these, at room temperature, the soft and elastic phase is the continuous phase while the cured phase, polystyrene, is dispersed. The hardened polystyrene gives the material its strength. When machined, the temperature is raised above the glass temperature of the polystyrene whereby it melts and the material can flow. Because. of the butadiene double bonds in SBS, this thermoplastic elastomer has poor weather resistance. Bed in SBS and SEBS, the polybutadiene and its hydrogenated form are the continuous phase, hence these beds have low oil resistance. Another disadvantage of SEBS is its complicated manufacturing method and consequently high price.

An example of materials belonging to the second major group of thermoplastic elastomers, a thermoplastic elastomer blend, are mixtures of polypropylene and ethylene-propyl rubber or ethylene-propylene rubber. In these, the cured phase polypropylene is the continuous phase while the dm soft phase is dispersed. Because the continuous phase is polypropylene, these materials possess good oil resistance properties. These are done by mixing the two main components as well as various additives in an extruder. The phase separation is made stable by crosslinking dm dispersed rubber phases, see e.g. US 4,594,390.

The present invention describes a method of manufacturing m thermoplastic elastomer with m polyolefin as continuous phase and m rubbery polyacrylate as dispersed phase. This product is made in a reactor and, if necessary, can be crosslinked already during polymerization in the reactor. Thus, no separate vulcanization step is needed. Since polyolefin is the continuous phase and since the elastomeric part of the product is a polyacrylate, the product has very good weather and oil resistance properties.

This invention thus allows the preparation of a polyolefin based thermoplastic elastomer without a separate vulcanization step and with a dispersed phase polyacrylate. The method is like polymerizing m acrylate inside a polyolefin matrix. The acrylate is such an acrylate whose polymer has elastic properties and whose glass temperature is lower than room temperature. Where the acrylates polymerize, they form a dispersed phase in the polyolefin matrix. Since the acrylates are polymerized with free-radical polymerization technique, some of the polyacrylate chains will be grafted onto the polyolefin chains, resulting in good adhesion between the continuous polyolefin phase and the dispersed polyacrylate phase. By using m less amount of diacrylate together with the acrylates, one can crosslink the dispersed polyacrylate phase to the desired crosslink density.

The inventive aspect of this patent is that polyolefin-polyacrylate blend made by polymerizing an acrylate within a polyolefin matrix has polyolefin as continuous phase and polyacrylate as dispersed phase, which allows the material to have thermoplastic properties. Furthermore, the material is characterized by the fact that the dispersed elastic polyacrylate phase can be crosslinked already during the polymerization and that the material can thereby be coated without disturbing the structure with dispersed polyacrylate areas. The cross-linking of the polyacrylate phase is especially important in cases where the adhesion between polyolefin matrix and polyacrylate can be expected to be low as when the polyolefin is the homopolyethylene or polypropylene. Upon heating during processing, the polyolefin melts and becomes liquid, but the soft-dispersed polyacrylate retains its dispersed form, since it is cross-linked.

The actual fabrication of the material can be done according to some of the methods found in the patent literature to polymerize monomers within polyolefin matrices with free-radical polymerization technology, for example in accordance with the Finnish patent 88170. In principle, the production is done by literating the acrylate monomer and possibly diacrylate monomers as well as initiator is absorbed into the polyolefin particles. The impregnation temperature is so low that no decomposition of the initiator occurs, but nevertheless is so high that the monomer and initiator increase penetration into the polyolefin particles. When all the monomer and initiator have been absorbed into the polyolefin particles, the temperature and initiator are decomposed and initiate polymerization of the acrylates. During the impregnation, the polyolefin particles swell to some extent depending on the amount of monomer added, but the particles retain their particle structure during both impregnation and polymerization.

In the following, the invention is described in detail.

polyolefin

Useful polyolefins include high density polyethylene, low density polyethylene and linear low density polyethylene. The polyethylene may be as a homopolymer or as a copolymer. As comonomers for ethylene may be vinyl acetate, vinyl chloride, propylene or any other α-olefin, C1-C4 alkyl acrylates and methacrylates, acrylic acid and methacrylic acid, hydroxyalkyl acrylates and methacrylates, glycidyl acrylate and methacrylate, dienes such as hexadiene-1,4 , 5, heptadienl, 6, 2-methylpentadiene-1,4, octadiene-1,7, 6-methylheptadiene-1, and polyenes such as octatriene and dicyclopentadiene. Also useful are ethylene-α-olefin polyester polymers. As α-olefin suitable for example. propylene, butene, pentene, isoprene, hexene or mixtures thereof and as polyene e.g. hexadiene-1,4, hexadiene-1.5, heptadiene-1.6, 2-methylpentadiene-1,4, octadiene-1,7,6-methylheptadiene-1,5, octatriene, dicyclopentadiene. In it₄ If the ethylene polymer is a copolymer, the proportion of ethylene in the copolymer should be at least 50% by weight.

The polyolefin may also be polypropylene and its copolymers. The propylene copolymers should consist of over 50% by weight of propylene and may be a random or block copolymer of propylene and ethylene. Other α-olefins may also be comonomers, such as hexadiene-1,4, hexadiene-1,5, heptadiene-1,6, 2-methylpentadiene-1,4, octadiene-1,7, 6-methylheptadiene-1,5 and polyenes such as octatri and dicyclopentadiene.

The polyolefin may be in any form heist, but is most preferably in pellet form having a diameter of 0.5 -10 mm. Where the polyolefin is in particulate form, the material's finishing, washing and drying are facilitated.

acrylate monomer

Suitable as monomers are acrylates and methacrylates whose polymers have low glass temperatures, ie. are rubbery at room temperature and at lower temperatures heist at temperatures below -20 ° C. The glass temperature of the polyacrylate determines the lower use temperature of the material, below the glass temperature, the polyacrylates are hardened and inelastic and the material loses its elastomeric properties. Suitable acrylates are alkyl acrylates having 1 or heist 2 or more carbon atoms in the alkyl chain. Methacrylates which have sufficiently low glass temperatures are alkyl methacrylates having 4 or more or heist 8 or more carbon atoms in the alkyl chain. These monomers can be used separately or in mixtures containing two or more monomers. Along with the aforementioned monomers, smaller amounts of monomers having fewer carbon atoms in the carbon chain can also be used than the aforementioned. This allows you to fine-tune the glass point of the final product. As comonomers, acrylates or methacrylates may also be used which, in addition to the ester bond, also contain other polar groups, e.g. alkoxy or hydroxy groups. Examples of these are methoxy and ethoxyethyl acrylate, methoxy and ethoxybutyl acrylate, hydroxyethyl and hydroxypropyl methacrylate. By using these comonomers one can improve the oil resistance of the product. Also, smaller amounts of other non-acrylate monomers polymerizable by free radical polymerization technique can be copolymerized with the above acrylates and methacrylates.

The amount of acrylate

In principle, one can of course add as small amounts of acrylate as the heist, but in order to obtain a material which can be said to be a thermoplastic elastomer, tens of percentage points should be added. The amount of acrylate to be polymerized inside the polyolefin also depends on the polyolefin used and on whether oil is added or not. Without the oil and filler additive, for polypropylene based materials of this invention, 50-90% by weight of acrylate is needed, the proportion of the polypropylene is thus 50-10% by weight. For polyethylene based thermoplastic elastomers of this invention, the required amount of acrylate varies depending on whether or not the polyethylene contains comonomers. Without oil and filler additives, the amount of acrylate can range from 50-90% by weight for the homopolyte down to 20-90% by weight for polyethylene grades containing up to 30% by weight comonomer. The effect of the acrylate amount on the softness and other properties of the material is more clearly expressed by the expert.

Addition of oil

Adding oil can make the material softer. Alternatively, it can be said that by adding oil one can reduce the amount of polyacrylate, relative to the amount of polyolefin, to achieve a certain softness. The amount of oil added can be 0-40% by weight in the final product. The oil may be added together with the acrylate and initiator and thus penetrate into the polyolefin particles during impregnation and / or during polymerization. The oil can also be added to the reactor only after the polymerization is completed and is allowed to impregnate in the polyolefin-polyacrylate particles at elevated temperature. Another way is to add the oil to the polyolefin-polyacrylate material in an extruder. Useful oils are oils that are normally used to soften rubber, e.g. paraffinic, naphthenic, aromatic and synthetic oils, and plasticizers for thermoplastics such as e.g. dioctylphthalate.

Additive of filler

Another way to modify the material so that the properties of the product become desirable is to add filler. By adding fillers, for example. increase the hardness and operating temperature. The filler can be added to the polyolefin-polyacrylate mixture in an extruder. The filler can of course also be included in the polyolefin used as the starting material for the polymerization. Conventional fillers can be used, e.g. taik, kaolin, CaCO₃, silica. The amount of filler can be 0-70% by weight in the final product.

Composition of the final product

In addition to the polyolefin and polyacrylates, the final product also contains oil and fillers. The proportion of polyolefin and polyacrylate in the final product can thus vary within very wide limits, depending on, in addition to the amount of oil and filler, also the polyolefin used. Thus, if the polyolefin is polypropylene, the polypropylene / polyacrylate ratio may vary between 0.1 and 2. If the polyolefin is polyethylene or an ethylene copolymer, the ratio may vary between 0.1 and 5.

Crosslinking of the polyacrylates

Some acrylates spontaneously form gel without the use of diacrylate. In such cases, it is always necessary to use diacrylate to further crosslink the polyacrylate. A well-known example of an acrylate that spontaneously forms a gel is butyl acrylate. The need for the use of diacrylate also depends on the adhesion between the dispersed polyacrylate and the continuous polyolefin matrix. If the adhesion between the phases is high, the tendency of the dispersed polyacrylate to agglomerate and form larger phase structures is lower than in the case that the adhesion is poor. If the polyolefin is a polyethylene containing polar groups, the adhesion may be so good that only small amounts or no diacrylate at all need be used. On the other hand, if the polyolefin is a homopolyethylene or polypropylene, the adhesion between the phases is low and for the dispersed polyacrylate particles to count processing, without both agglomerating and forming large cohesive polyacrylate domains and partly without a phase inversion leading to the polyacrylate being continuous. or at least the cocontinuous phase, the polyacrylates should be cross-linked with a diacrylate. The crosslinking is most convenient already done in the reactor by adding an acrylate having two or more double bonds. During polymerization, these acrylates with two or more double bonds will be copolymerized with different polyacrylate chains, thereby crosslinking the polyacrylate particles. Examples of suitable crosslinkers are hexanediol diacrylate or dimethacrylate, butanediol diacrylate or dimethacrylate. The amount of crosslinker is 0-15% by weight of the acrylate amount. Since the amount of cross-linkers can be quite low, in addition to these multifunctional acrylates, other monomers with two or more double bonds can be used without significantly affecting the properties of the product, e.g. divinylbenzene.

initiator

Initiators that can be used to polymerize the acrylates are initiators conventionally used in the free radical polymerization of vinyl monomers and include organic peroxides such as e.g. benzoyl peroxide, lauroyl peroxide, t-butyl perbenzoate, t-butyl peroxy-2-ethylhexanate, t-butyl peroxide, dicumyl peroxide, di-t-butyl peroxide, bis (t-butyl peroxyisopropyl) benzene, t-butyl peroxyisopropyl carbonate, 2,5-dimethyl butyl peroxyhexane, 2.5dimethyl-2,5-di- (tert.butylperoxy) hexyn-3, and azo compounds such as e.g. azobisisobutyronitrile and azobisdimethylvaleronitrile.

More than one initiator can be used simultaneously so that the polymerization is started at low temperature with a low temperature initiator and completed at higher temperature with a high temperature initiator ”. The amount of initiator may be between 0.01 and 2 wt.%, Heist between 0.1 and 1 wt.%, Based on 100 parts by weight of monomer.

Preparation, including impregnation and polymerization

In principle, the preparation of this polyolefin-polyacrylate material can be done according to the methods found in the patent literature to first impregnate acrylate and initiator into the polyolefin particles and then polymerize the acrylates by raising the temperature. The impregnation of the acrylate and the initiator can thus be done completely in the absence of water, with the addition of a little water, by adding the water where more than half of the acrylates have been impregnated (these three methods are described in principle in Finnish patents FI85496, F186642 and FI88170) or in presence of the entire amount of suspension water (as in US patent US4,412,938). The impregnation can also be done by adding slowly to the aqueous suspension containing the polyolefin particles for several hours the acrylate and the initiator at elevated temperature, while the acrylate also impregnates the polymerization of the acrylate (this method is described in principle in German patent DE2907662).

An advantageous embodiment is in accordance with the Finnish patent FI88170. With this method, a maximum of about 65% by weight of acrylate can be impregnated and polymerized in the polyolefin particles in a polymerization step. If you want to further increase the polyacrylate content to obtain a softer elastomer, the product from the first polymerization step can be impregnated with more acrylate and initiator and then polymerized. In this way, the polyacrylate content can be gradually increased to almost 100%. This stepwise increase of the polyacrylate content does not necessarily have to be done in completely separate polymerizations. It is also possible to lower the temperature to the impregnation temperature at the end of the first polymerization and then pump in the desired additional amount of acrylate and initiator. After the acrylate and initiator have been absorbed into the particles, the temperature is raised and the acrylate polymerizes.

If the polymerization is done in two or more steps and it is desired to cross-link the polyacrylates, it is appropriate to do the first polymerization without diacrylate. In this way, the polyacrylates will form a dispersed phase during the first polymerization step, since the polyacrylate chains are not cross-dogs and therefore due to. polarity differences compared to the polyoleftn phase are approaching each other. In the second polymerization step, the added acrylates and diacrylates will preferably adhere to the polyacrylate particles already existing in the polyolefin matrix and polymerize and crosslink there. The added diacrylate will hardly react with the polyacrylate formed during the first polymerization step, but since the acrylate and diacrylate polymerize in the presence of the already existing polyacrylate, it will also be physically cross-linked to the chemically cross-linked polyacrylate formed in the second polymerization step. entanglements.

Properties of the polymerization product

Since the elastomer in this thermoplastic elastomer is a polyacrylate, the product has especially good oil resistance, weather resistance and aging resistance. The properties of the thermoplastic elastomer manufactured according to this patent depend on the polyolefin used: homo-, block- or randomopoly propylene, homopolyethylene or polyethylene containing any comonomer. The properties that can be influenced by polyolefin wire are in particular the product's temperature resistance, chemical resistance and adhesion properties. The properties of the product, such as hardness, toughness and elasticity, are influenced by the type of acrylate, the amount of acrylate and the crosslinking density. If the polyolefin is polypropylene, the product has particularly good temperature resistance, water resistance and oil resistance. Characteristic of a polyethylene-based product is its good weather resistance and oil resistance. Of course, the properties of the product can also be adjusted by the addition of filler. Fillers can also be included in the starting polyolefin already. The properties of the product are elucidated in the experiments.

Use of the product

Materials made in accordance with this invention can be used in applications where other thermoplastic elastomers or conventional rubbers are used. Typical applications are similar in the construction industry, for example. sealing strips and gaskets, for example in the automotive industry. protective bellows at power transfer points and as interior material for the instrument panel, within the electrical industry, for example. materials for cables, connectors and various boxes. This material is also used for all kinds of mechanical articles such as. handles, wheels and cases.

io The material can be processed by conventional thermoplastic processing methods such as e.g. extrusion, injection molding and blow molding. Since the continuous phase is a polyolefin, this material is excellent for coextruding with polyolefins. In the processing, conventional auxiliaries such as antioxidants, fillers and oil can be added.

Examples 1-16

To a reactor was added polyolefin pellets, acrylate, initiator (s) and optionally 1,6-hexanediol diacrylate. The reactor was filled and emptied with 7-8 bar nitrogen three times to remove oxygen in the reactor. Thereafter, the temperature was raised to the impregnation temperature with stirring and maintained there until most of the acrylate and initiator or initiators have been impregnated. The impregnation time was 1-3 hours, depending on polyolefin quality. Thereafter, it is also added with nitrogen flushing the suspension water. The suspension water contained tri-calcium phosphate and sodium dodecylbenzenesulfonate as the suspending agent.

The temperature of the suspension water was the same as the impregnation temperature. After the addition of water, the temperature was raised so much that the initiator bent down and initiated the polymerization. The polymerization lasted 7-12 hours depending on the polyolefin quality. After the polymerization, the polymerization product was washed and dried. A variety of polyolefin-polyacrylate materials were made according to this sample, see Table 1 below. All polypropylene-based materials with more than 50% by weight of acrylate were made in two stages, so that the product from the first polymerization step contained 50% by weight of polyacrylate. Experiment 9 was also done in two steps while experiment 10 was done in three steps. The structure of dispersed polyacrylate domains emerges from Figure 1, where the product from the first polymerization step in Experiment IS has been photographed with transmission electron microscope. In the figure, the dark dispersed phase is polyacrylate while the light continuous phase is the polyp. From the figure it should be noted that the diameter of the polyacrylate particles is about 0.5 µm.

Table 1. Experiments 1-16.

<td>Exp No.</td><td>Polyolefin¹pangs.</td><td>SI s</td><td>Acrylate * type*</td><td>weight-%</td><td>Diaby- latvikt- %</td><td>Initiator type *</td><td>Impre- g.'C</td><td>Polym. • C</td><td>GCL¹ %</td>

<td> 1</td><td>EVA28</td><td> 5</td><td>ECHO</td><td> 40</td><td> -</td><td>AIBN, BPO</td><td> 37</td><td> 55-100</td><td> 62</td>

<td> 2</td><td>EVA28</td><td> 5</td><td>EHA</td><td>SE</td><td> -</td><td>AIBN, BPO</td><td> 41</td><td> 55-100</td><td> 56</td>

<td> 3</td><td>EVA18</td><td> 10</td><td>EHA</td><td>SE</td><td> -</td><td>BPO, BPIC</td><td> 51</td><td> 75-115</td><td> 61</td>

<td> 4</td><td>EVA9</td><td> 8</td><td>EHA</td><td>SE</td><td> -</td><td>BPIC</td><td> 69</td><td> 90-120</td><td> 54</td>

<td> 5</td><td>EBA27</td><td> 4</td><td>EHA</td><td>SE</td><td> -</td><td>AIBN, BPO</td><td> 44</td><td> 55-100</td><td> 77</td>

<td> 6</td><td>EBA17</td><td> 7</td><td>EHA</td><td>SE</td><td> -</td><td>BPO</td><td> 72</td><td> 70-100</td><td> 70</td>

<td> 7</td><td>EBA17</td><td> 7</td><td>BA</td><td>SE</td><td> -</td><td>BPIC</td><td> 61</td><td> 85-115</td><td> 55</td>

<td> 8</td><td>EBA17</td><td> 7</td><td>BA</td><td>SE</td><td> 1.0</td><td>BPIC</td><td> 69</td><td> 85-115</td><td> 60</td>

<td> 9</td><td>EBA7</td><td> 1</td><td>BA</td><td> 64</td><td> 03</td><td>t-BPB</td><td> 86</td><td> 90-120</td><td> 83</td>

<td> 10</td><td>LLDPE</td><td> 65</td><td>BA</td><td> 69</td><td> 1.6</td><td>DHBP</td><td> 101</td><td> 110-135</td><td> 53</td>

<td>¹¹</td><td>Random PP</td><td> 20</td><td>BA</td><td>SE</td><td> 0.1</td><td>DYBP</td><td> 116</td><td> 125-150</td><td> 53</td>

<td> 12</td><td>Random PP</td><td> 20</td><td>BA</td><td> 68.5</td><td> 1.6</td><td>DYBP</td><td> 112</td><td> 130-150</td><td> 74</td>

<td> 13</td><td>Random PP</td><td> 20</td><td>BA</td><td> 67</td><td> 3.1</td><td>DYBP</td><td> 108</td><td> 130-150</td><td> 67</td>

<td> 14</td><td>Random PP</td><td> 20</td><td>BA</td><td> 74</td><td> 1.5</td><td>DYBP</td><td> 117</td><td> 130-150</td><td> 74</td>

<td>ICE</td><td>Random PP</td><td> 20</td><td>EHA</td><td> 68,4</td><td> 1.6</td><td>DYBP</td><td> 116</td><td> 130-150</td><td>⁶⁴</td>

<td> 16</td><td>Block PP</td><td> 40</td><td>EHA</td><td> 72.5</td><td> 3.3</td><td>DYBH</td><td> 120</td><td> 135-150</td><td>J</td>

1) All polyolefins used are Neste's commercial qualities.

2) Gel content determined in boiling xylene for 16 hours.

3) The melt index is determined for the polyethylene grades at 190 ° C and 2.16 kg and for polypropylene at 230 ° C with 2.16 kg.

4) EHA - ethyl hexyl acrylate, BA = butyl acrylate

5) AIBN = azobisisobutyronitrile, BPO = benzoyl peroxide, BPIC = tert-butyl peroxyisppropyl carbonate, t-BPB = tert-butyl peroxybenzoate, DYBP = 2,5-dimethyl 2,5-di (tertbutylperoxy) -hexyn-3, DHBP = 2.5 dimethyl 2,5-di (tert-butyl peroxy) hexane.

6) Diacrylate = 1,6-hexanediol diacrylate

The polymeric materials made according to Table 1 were injection-molded into sheets of 80 x 80 mm and thickness 2 mm at 165-205 ° C, depending on the polyolefin used. The necessary test bars were punched from the boards. The mechanical properties are shown in Table 2. Fracture elongation and fracture strength here measured on test rods which are punched transversely to the flow direction at the injection molding.

Table 2. Mechanical properties of the materials in Experiments 1-16.

<td>Exp. No.</td><td>Polyol cfu kv tiilet</td><td>AkiyUt '7P</td><td>S</td><td>dia- kr.v- ICT «</td><td>oal «</td><td>Bratt- lAjni- · »*«</td><td>Crime- rtytka * MP »</td><td>IRHiy</td><td>Rcatkompr. ' *</td><td>RcaHSjninf * «</td>

<td> 1</td><td>EVA2S</td><td>EHA</td><td> 40</td><td> -</td><td> 62</td><td> 15»</td><td> 54</td><td> 65</td><td> -</td><td> 24</td>

<td> 2</td><td>EVA28</td><td>ECHO</td><td>SE</td><td> -</td><td> 56</td><td> 177</td><td> 3,2</td><td> 52</td><td> -</td><td> 17</td>

<td> 3</td><td>EVA18</td><td>EHA</td><td>SE</td><td> -</td><td> 61</td><td> 107</td><td> 2.7</td><td> 61</td><td> -</td><td> 20</td>

<td> 4</td><td>EVA9</td><td>EHA</td><td>SE</td><td> -</td><td> 54</td><td> 90</td><td> 3.2</td><td> 75</td><td> -</td><td> 23</td>

<td>S</td><td>EBA27</td><td>EHA</td><td>SE</td><td> -</td><td> 77</td><td> 75</td><td> 1.9</td><td> 56</td><td> -</td><td> 16</td>

<td> 6</td><td>EHA17</td><td>EHA</td><td>SE</td><td> -</td><td> 70</td><td> 449</td><td> 5.4</td><td> 67</td><td> -</td><td> 16</td>

<td> 7</td><td>EBA17</td><td>BA</td><td>SE</td><td> -</td><td> 55</td><td> 528</td><td> 6.1</td><td> 75</td><td> 30</td><td> 33</td>

<td>s</td><td>EBA17</td><td>BA</td><td>SE</td><td> 1.0</td><td> 60</td><td> 354</td><td> 7.1</td><td> 76</td><td> 20</td><td> 25</td>

<td> 9</td><td>EBA7</td><td>BA</td><td>M</td><td> 0.5</td><td>S3</td><td> 209</td><td> 6.3</td><td> 75</td><td> 22</td><td> 16</td>

<td> 10</td><td>LXDPE</td><td>BA</td><td> 69</td><td> 1.6</td><td> 73</td><td>I7S</td><td> 5.1</td><td> 82</td><td> 38</td><td> 37</td>

<td> 11</td><td>Random PP</td><td>BA</td><td>SE</td><td> 0.1</td><td>S3</td><td> 198</td><td> 8,4</td><td> 97</td><td> -</td><td> 66</td>

<td> 12</td><td>Random PP</td><td>BA</td><td> 68.5</td><td> 1.6</td><td> 74</td><td> 169</td><td> 74</td><td> 90</td><td> 43</td><td> 40</td>

<td> 13</td><td>Random PP</td><td>BA</td><td> 67</td><td> 3.1</td><td> 67</td><td> 142</td><td> 8.9</td><td> 92</td><td> 31</td><td> 32</td>

<td> 14</td><td>Random PP</td><td>BA</td><td> 74</td><td> 1.5</td><td> 74</td><td> 128</td><td> 5.6</td><td> 81</td><td> 26</td><td> 16</td>

<td>¹⁵</td><td>Random PP</td><td>EHA</td><td> 61,4</td><td> 1.6</td><td> 64</td><td> 127</td><td> 5.9</td><td> 88</td><td> 43</td><td> 43</td>

<td>LL</td><td>Block PP</td><td>EHA</td><td> 724</td><td> 3,5</td><td></td><td></td><td></td><td></td><td></td><td></td>

1) Break elongation measured in accordance with ISO 37

2) The breaking strength measured according to ISO 37

3) Hardness, IRHD, measured in accordance with ISO 48

4) Residual compression after 24 hours at room temperature according to ISO 815

5) Residual elongation after 24 hours at room temperature according to ISO 2285

The amount of polyacrylate most affects the hardness of the product, the more polyacrylate the softer the material, compared to Experiments 1 and 2 and Experiments 11-15. Of the mechanical properties, the polyolefin grade likasi most influences the hardness, compare 2, 3 and 4, and S and

6th The amount of diacrylate affects all mechanical properties. More diacrylate improves strength, crustal compression and residual tightening but reduces fracture elongation, compare 7 and 8, as well as 12 and 13.

In Table 3, the product from Experiment 7 is compared with a commercial SBS grade, Dexco's Vector-2411D, at S3 ° C. These have both about the same hardness and the same maximum allowable operating temperature, 60-70 ° C. From the table, it is clear that SBS has significantly lower oil resistance than the product from Experiment 7. Likewise in Table 3, the product from Experiment 13 is compared with Monsanto's commercial thermoplastic elastomer Santoprene 20180 at 100 ° C. The product from Experiment 13 has polypropylene as polyolefin and continuous phase and can therefore be compared with Santoprene, which also has polypropylene as continuous phase. Santoprene has ethylene-propylene-diene rubber as an elastomeric phase. Bed has the same hardness. From the table it is clear that the product from Experiment 13 has significantly better oil resistance than Santoprene in the ASTM1 and ASTM2 oils. In ASTM3 oil, Santoprene is slightly better.

Table 3. The oil resistance, measured as volume expansion, of materials made according to this invention compared to commercial thermoplastic elastomers according to ISO 1817. For Experiment 7 and SBS, 55 ° C was used and for Experiment 13 and Santoprene 100 ° C was used.

<td rowspan="2">ExpNr</td><td rowspan="2">Material</td><td rowspan="2">Hirdhet IRHD</td><td colspan="3">ASTM1 24 hours a day 7 days</td><td colspan="3">ASTM2 24 hours a day 7 days</td><td rowspan="2">ASTM3 24 hours a day 7 days XXX</td>

<td>X</td><td> *</td><td>X</td><td>X</td><td>X</td><td>X</td>

<td> 7</td><td>EBA17 FBA</td><td> 75</td><td> 8</td><td>hrs</td><td> 16</td><td> 14</td><td> 28</td><td> 34</td><td> 51 89 -</td>

<td></td><td>SBS.Vector-241 ID</td><td> 82</td><td> 35</td><td> 50</td><td> 52</td><td> 98</td><td> 127</td><td> -</td><td> - . .</td>

<td> 13</td><td>PP PBA</td><td> 92</td><td> -</td><td> 8</td><td> 10</td><td> -</td><td> 22</td><td> 24</td><td> 58 58</td>

<td></td><td>Hall opera 201-80</td><td> 91</td><td> -</td><td> 18</td><td> 19</td><td></td><td> 31</td><td> 31</td><td> - 52 54</td>

Table 4. Ozone aging

The materials' resistance to aging at high temperature was tested by aging the materials at 70 ° C for 168 hours. Fracture elongation and fracture strength were measured on non-aged and aged material on test rods punched in the flow direction. The material from Experiment 7 was compared with a commercial SBS grade, Enichem's Europrene SOL T166, and a commercial SEBS grade, Neste Polymer Compounds 6503. These three materials are comparable in terms of toughness and temperature of use. From Table 5, it should be noted that the material from Experiment 7 has significantly better resistance to aging at elevated temperature. This is despite the fact that the material from Experiment 7 was not stabilized with antioxidants. The table also compares a polypropylene based material made according to experiment 13 with the Santoprene grade 201-80.

Table 5. Change in fracture elongation and fracture strength in aging at 70 ° C for 168 hours. The change is stated as a percentage change between non-aged and older material.

<td>Exp No.</td><td>Material</td><td>HirdheClRHD</td><td>Brottejniag «</td><td>Broutyrica MPa</td><td>FMndriqg, Crime &amp; jning</td><td>« BroMtyria</td>

<td> 7</td><td>EBA17 -PBA</td><td> 75</td><td> 129</td><td> 5.7</td><td> +4,9</td><td> +7.5</td>

<td></td><td>SBS 166</td><td> 75</td><td> 540</td><td> 113</td><td> -15,2</td><td> -36,2</td>

<td></td><td>SEBS 6503</td><td> 75</td><td> 305</td><td> 5.8</td><td> -21,0</td><td> -4.9</td>

<td> 13</td><td>PP BPA Sanloprco 201-80</td><td> 91</td><td> 126</td><td> 103</td><td> -15,4</td><td> +5.1</td>

Experiment 17-20

A material made in accordance with Experiment 7, but with the diacrylate amount of 0.5% by weight, was filled with three different fillers, 23-41% by weight in the final product, in a cross-screw extruder at 200 ° C. From Table 4 it can be seen that hardness increases with increasing filler content. Other mechanical properties are virtually unchanged compared to the unfilled material in Experiment 17.

Table 4. Effect of fillers on the mechanical properties of the product from Experiment 17.

<td>- No.</td><td>Folyolefin quality</td><td>acrylate «yp</td><td> «</td><td>Diakr. weight-*</td><td>Oel »</td><td>Bratt- tdjmqf¹ *</td><td>Brotta- tyrfca * MPa</td><td>IRHD '</td><td>Raalkom- pr? %</td><td>XMt- up * «</td>

<td> 17</td><td>EBA17</td><td>BA</td><td>SE</td><td>0.S</td><td> 63</td><td> 360</td><td> 6.6</td><td> 71</td><td> 28</td><td> 32</td>

<td> 18*</td><td>EBA17</td><td>BA</td><td>SE</td><td> 0.5</td><td> -</td><td> 270</td><td> 6.2</td><td> 84</td><td> 24</td><td> 32</td>

<td> 19’</td><td>EBA17</td><td>BA</td><td>SE</td><td>0.S</td><td> -</td><td>23S</td><td> 6.0</td><td> 67</td><td> 30</td><td> 39</td>

<td> 20*</td><td>EBA17</td><td>BA</td><td>SE</td><td>os</td><td> -</td><td> 322</td><td> 7.1</td><td> 87</td><td> 27</td><td> 41</td>

1) Break elongation measured in accordance with ISO 37

2) The breaking strength measured according to ISO 37

3) Hardness, IRHD, measured according to ISO 48

4) Residual compression after 24 hours at room temperature according to ISO 815

5) Residual elongation after 24 hours at room temperature according to ISO 2285

6) Additive filler Taik, Finntalk 20 10% by volume (23% by weight)

7) Additive filler CaCO ,, Nordkrone 40 20% by volume (41% by weight)

8) Addition of CaCO, Winnofil S 20% by volume (40% by weight)

Experiments 21, 22 and 23

To a material made entirely in accordance with Experiment 13, 10 wt.% Oil and 0.3 wt.% Antioxidant, Irganox 1520, were added in a single screw extruder at 205 ° C. As oils were used a paraffinic oil, Nypar 40 (Neste-Alfa Oy), and a naphthenic oil, Nytex 840 (Nynäs Petroleum). Thus, the final product composition is 10% by weight oil, 63% by weight polybutyl acrylate and 27% by weight polypropylene. The material was injection molded into disks from which the sample rods were punched transversely to the flow direction. From the results in Table 6, it can be seen that the material through the oil additive has become softer without losing other mechanically good properties, residual compression and residual elongation, towers have improved.

Table 6. Addition of 10% by weight of oil to a polypropylene-polybutylacrylate material.

<td>B ,.</td><td>ogakvalitet</td><td>weight-%</td><td>Brotnejaigg¹ «</td><td>BrotMyrka¹MPa</td><td>QUID '</td><td>ReMkompr.⁴ «</td><td> «</td>

<td> 21</td><td> -</td><td> -</td><td> 138</td><td> 9,3</td><td> 93</td><td> 37</td><td> 32</td>

<td> 22</td><td>Nytex M0</td><td> 10</td><td> 131</td><td> «.0</td><td>n</td><td> 33</td><td> 27</td>

<td> 23</td><td>Nypar40</td><td> 10</td><td> 142</td><td>«.s</td><td> 89</td><td> 33</td><td> 25</td>

1) Break elongation measured in accordance with ISO 37

2) The breaking strength measured according to ISO 37

3) Hardness, IRHD, measured in accordance with ISO 48

4) Residual compression after 24 hours at room temperature according to ISO 815

5) Residual elongation after 24 hours at room temperature according to ISO 2285

Experiments 24 and 25

These experiments were done, like Experiment 13, with the difference that 6% by weight of oil was added to the reactor with the acrylates in the second polymerization step. The entire amount of oil was absorbed into the pellets and the composition of the final product is thus 6% by weight oil, 70% by weight polybutyl acrylate and 24% by weight polypropylene. From the test results in Table 7 below, it is seen that the material, in comparison with Experiment 13, becomes considerably softer and residual elongation and residual compression become slightly better. Break elongation and breaking strength are small.

Experiment 26

This experiment was done, like Experiments 24 and 25, with the difference that oil was added in both polymerization steps, 6% by weight in the first and 11% by weight in the second polymerization step. This gives the final composition: 14 wt% oil, 30 wt% polypropylene and 56 wt% butyl acrylate (including 2.2 wt% diacrylate). The oil was Nytex 840. The test results are shown in Table 7 below.

Experiments 27 and 28

As a starting material for oil and filler experiments, a polypropylene based material made similar to Experiment 13 was used, with the difference that the amount of butyl acrylate in the first polymerization step was 37 wt% and in the second polymerization step 34 wt% (4-3 wt%). This gives the final composition 60 wt% polybutyl acrylate and 40, including 3 wt% diacrylate.

Table 7. Impact of oil and fillers on the properties.

<td>Exp.</td><td>Oljakvalilet</td><td>weight* %</td><td>PP WE-"</td><td>PBA we-"</td><td>FyU- mcdel we-"</td><td>Broe- töjaing¹ «</td><td>Broa&gt; - Tyrka¹MPa</td><td>ntHD *</td><td>Rcatkom- pr? *</td><td>ReMftjoi- es' "</td>

<td> 24</td><td>Nypar40</td><td> 6</td><td> 24</td><td> 70</td><td> -</td><td>ns</td><td> 6,9</td><td> 14</td><td> 31</td><td> 31</td>

<td> 25</td><td>NyuxMO</td><td> 6</td><td> 24</td><td> 70</td><td> -</td><td> 126</td><td> 7.5</td><td> 85</td><td> 27</td><td> 29</td>

<td> 26</td><td>NyuxMO</td><td> 14</td><td> 30</td><td> 46</td><td> -</td><td></td><td></td><td></td><td></td><td></td>

<td> 27</td><td>Nypar40</td><td> 20</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

<td>IL</td><td>Nypar4O</td><td> 20</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td>

1) Break elongation measured in accordance with ISO 37

2) The breaking strength measured according to ISO 37

3) Hardness, IRHD, measured in accordance with ISO 48

4) Residual compression after 24 hours at room temperature according to ISO 815

5) Residual elongation after 24 hours at room temperature according to ISO 2285