A method for improving the adhesion of amine-containing organopolysiloxane composition

[Detailed Description of the Invention]

This invention relates to an amine content room temperature hardenability (vu-Icanizable) organopolysiloxane constituent (RTV) and the method of promoting the cure rate of an amine content organopolysiloxane constituent, and improving adhesion with a generation elastomer and a base especially. Room temperature hardenability organopolysiloxane is commercially publicly known. There are usually 2-ingredient system and a 1-ingredient system in a room temperature hardenability organopolysiloxane constituent, and after mixing both ingredients, the composition is hardened automatically, and by the latter, a constituent is hardened under existence of humidity, oxygen, or other substances, and forms an elastomer at the former. A conventionally publicly known 1-ingredient system RTV organopolysiloxane constituent, It was manufactured by mixing It was diorganopolysiloxane with a hydroxyl group and an end reactivity machine like an alkoxy group, and the amine substitution ORGANO silicon compound which the amine machine has combined with silicon by Si-N combination. In a specific industrial use, a disadvantageous point exists in these 1-ingredient system amine content organopolysiloxane. For example, if amine content organopolysiloxane touches the humidity in the atmosphere, it will form a coat in the surface. This coat generated on the surface of the hardening room temperature hardenability constituent at last bars hardening of the substance under it. In this way, for the reason, advance of required hardening becomes difficult more, and adhesion to the base of the generated silicone elastomer becomes poor. Once the amine content organopolysiloxane constituent which the amine substitution silicon compound containing aliphatic amine used as a bridge or a Reaction agent touches the humidity in the atmosphere, the pot lives (pot-life) will receive restriction very much. In the case of many industrial uses, it is essentially important for a constituent to have long pot lives, but once it applies simultaneously, it will be required that it should harden quickly and should bring about good adhesion. In U.S. Pat. No. 4170700 (Sweet), The method of promoting the case hardening of a room temperature hardenability constituent is indicated by by exposing the constituent containing hydroxyl end organopolysiloxane and an amine substitution silicon compound to the carbon dioxide which exists in atmospheric humidity and the overinside of the atmosphere. In U.S. Pat. No. 3923736 (Nitzshe etc.), the room temperature hardenability organopolysiloxane constituent which has long pot lives is indicated. This thing is chemical-formula =NCH (CH).₃)C₂H₅The amine substitution ORGANO silicon analogue include at least three silicon combination per Molecules of, and the diorganopolysiloxane which has an end group which is easy to condense are contained. Generally, if amine content organopolysiloxane is exposed to carbon dioxide and humidity, case hardening will be promoted, but the elastomer which arose as a result does not show good adhesion. Then, the object of the present invention is to provide the method of improving adhesion to the base of an organopolysiloxane constituent. Other objects of this invention are to provide the method of improving the adhesiveness of a bridge or the organopolysiloxane constituent which contained the amine substitution silicon compound as a Reaction agent. The object of this invention is to provide the manufacturing process of the silicone elastomer which has the surface with smooth gloss. The above-mentioned object and others will become clear from the next statement which carried out intermediary operation, although they were made into the method of this invention. In short, while this method promotes hardening of a room temperature hardenability organopolysiloxane constituent, it improves adhesion to the base of a generation elastomer. That is, it can Reaction in straight chain diorganopolysiloxane, this diorganopolysiloxane, and a bridge, and they are at least three Si-combination NR per molecule.₂The constituent which has a basis (here, R is a hydrogen atom or a carbonization-ized hydrogen machine) and an amine substitution silicon compound is applied to a base, and it heats under existence of humidity among [ before exposing this application base to the carbon dioxide which exists in the overinside of the atmosphere ] exposure. Although the diorganopolysiloxane used by this method could be new and what kind of diorganopolysiloxane which has an end reactivity machine could be sufficient, the end hydroxyl group was liked and used for the conventional room temperature hardening (RTV) constituent. The diorganopolysiloxane which has an end water oxidization machine is generally denoted by a following formula.<img file="JPH0341108B2_D0001.tif" />(Each R' is a 1 value hydrocarbon group or a substitution 1 value hydrocarbon group among a formula, x is average value 0.99-1.01, y is average value 1.99-2.01, it is x+y=3, and n is at least 3, preferably at least 50.) these Shiroki Sun is publicly known -- Then, for example, the [ United States patent ], 3294732; -- the 3127363; -- in addition to this, No. 3105061 is indicated completely. This Shiroki Sunpolymer is essentially a straight chain, and at least 90-mol % is [ most ] R.₂It is 'SiO unit. however -- it is the limited rate -- namely, -- desirable -- less than 5 mol % -- further -- desirable -- R'SiO not more than 2 mol %_3/2A unit, R₃'SiO_1/2A unit and/or SiO_4/2A unit exists. In the above-mentioned formula, each R' is a 1 value hydrocarbon group to 18 carbon atoms. A Alkyl machine like [ the example of the basis shown by R' ] methyl, ethyl, n-propyl, isopropyl, Dodecyl, and octadecyl; vinyl, Allyl, hexyl, and an alkenyl group like octadecenyl; cyclo butyl, cyclopentyl, cyclohexyl And a cycloalkyl machine like cyclodecyl; a cycloalkenyl group like cyclo butenyl, cyclo pentenyl, cyclohexenyl, and cyclo decenyl; phenyl, Xenyl, Naff Chill, and an aryl group like phenan sourire; Ben Chill, beta-phenylethyl And there are Aralkyl and the trill like beta-phenylpropyl, Xylyl, and an alkaryl group like ethyl phenyl. In the substitution hydrocarbon group denoted by R', they are o-, m-, and p-chlorophenyl and a Bromo phenyl group in beta-cyano ethyl, cyano propyl, cyano n-butyl, cyano n-propyl, and an omega cyano octadecyl group, There are the above-mentioned various alpha, alpha, and alpha-trifluoro trill, 3,3,3-trifluoro propyl, chloro, full Oro-, and Bromo- derivatives of a hydrocarbon group. The basis denoted by R' has carbon atoms fewer than eight pieces preferably, and more preferably R' expresses methyl, phenyl, vinyl, ethyl, propyl, 3 and 3, and 3-trifluoro propyl group. At least 50-mol% of R' machines should be aliphatic hydrocarbon machines which there were and contained four carbon atoms. [ many ] Of course, it is R' machine on one silicon atom in the usual case, It is the same or they are various units in a difference and the Shiroki Sun chain, They may be whether it is the same or a different homopolymer (example: dimethylsiloxane polymer), copolymers (example: dimethylsiloxane methylvinyl Siloxane-, phenylmethyl Siloxane polymer), and those mixtures. The Shiroki Sun Viscosity 10 in 25 degree[ from the fluid (viscosity 50cs. in 25 degreeC) of comparatively mobility / polymer ] C⁶Even the rubber-like substance of cs. can use it. Although the number of n in the above-mentioned general formula is at least 3, preferably at least 50, the above matter is clear from the ability to also take a large number like 2 million. desirable Shiroki Sunpolymer -- 25 degreeC -- the viscosity of the range by 200 to 200000 s -- with, it is. Other organopolysiloxane which can be used by this invention, Organic which can polymerize Organic containing a monomer or fatty series unsaturated and which can be polymerized It is the organopolysiloxane constituent which made the mixture of the monomer react to organopolysiloxane and manufactured it under existence of a free radical generating agent. Although these constituents belong to denaturation organopolysiloxane and the reaction product of fixity is included, as a time, graft (graft) organopolysiloxane, the ORGANO homopolymer, and a copolymer are contained. denaturation organopolysiloxane is common knowledge -- Then and its process -- United States patent the 3555109; -- the 3776875; -- the 3627836; -- the 3631087; -- it is indicated to other patents described into No. 3694478 and this book. -NR which this room temperature hardenability organopolysiloxane constituent could Reaction the denaturation organopolysiloxane which has organopolysiloxane and/or a reactant machine in that organopolysiloxane and bridge under anhydrous conditions, and was combined with one silicon atom₂(Here, R is the same as the above) It is manufactured by mixing with the amine substitution silicon compound which has an average of at least three bases per molecule. It is preferred that one R basis is hydrogen. A bridge or the amine substitution silicon compound used as a Reaction agent is amino Silane of a following formula. R¹_4-zSi(NR₂)_z(R is the same as the above among a formula, and it is each R.)¹It is a 1 value hydrocarbon group which has a carbon atom to 18 Is, and even if there is little z per molecule, it is an average of 3 number. Amino Silane used for a bridge or a Reaction agent contains 0 per an average of 3 per silicon atom or four amino substitution machines, and silicon atom or one Alkyl machine, the aryl group, the alkaryl group, or the aralkyl group. And 3 or 4 organic-functions Silang can be used, and hardening in which 4 organic-functions Silang is quicker than reason 3 organic-functions Silang where reactivity is stronger is obtained. Generally, 3 organic-functions amino Silane is formula R'Si (NR).₂)³At the same time -- 4 organic-functions Silang -- formula Si (NR)₂)₄It is come out and expressed. Inside of formula and R' is methyl, ethyl, propyl, or a Alkyl machine like octadecyl, It is an alkaryl group like phenyl or an aryl group like Anthracil, a cycloalkyl machine like cyclohexyl, an aralkyl group like Ben Jill, Trier, or Xylil, and each R is hydrogen and R.¹They are Alkyl, Aryl, cycloalkyl and Al Caleel who came out and stated, or an aralkyl group. The mixture of these amino Silane can also be used. A bridge or other amino substitution silicon compounds which are used for a Reaction agent are amino Siloxane of the following general formula. [Formula]

And it is amino Silyl alkane of the following general formula.<img file="JPH0341108B2_D0002.tif" />(The inside of a formula, R, R', and R)¹It is the same as Is the same as and R.²It is Saturation or an unsaturated 2 value hydrocarbon group with the carbon atom to ten Is, m is the numbers from 0 to 50, v is the numbers from 0 to 3, w is the numbers from 0 to 3, and v+w is at least 3. The above-mentioned R²It comes out and the 2 value saturated hydrocarbon machines with which it is expressed are methylene, ethylene, Pyropylene, butylene, Hexylene, Octylene, and a Decylene machine. R²It comes out and the 2 value unsaturated hydrocarbon machines with which it is expressed are Ethenylene, pro Penylene, butenylene, hexenylene, octenylene, and a decenylene machine. The example of a 2 value cyclic hydrocarbon machine is a phenylene group. Amino Silane, amino Siloxane, and amino Silyl alkane which are used for a bridge or a Reaction agent, For example, it is indicated in United States patents 3408325; (Hittmair etc.) 3464951st; (Hittmair etc.) 3452964(Creamer); 3644434 (Hittmair etc.) and (Pept etc.) 3816164 items. A bridge or other amino substitution silicon compounds which are used as a Reaction agent are amino Silazane of a following formula. (R₂N)_aR¹_bSiNH [R¹_b(R₂N)_cSiNH]_gSiR¹_b(NR₂)_a(R and R' is as having described above among a formula, and, as for 2 or 3, and b, 1 or 2, and g of 0 or 1, and c are [ a ] at least 1). This amino Silazane is indicated in U.S. Pat. No. 3032528 (Nitzsche etc.) quoted, for example in this book. Other amino substitution silicon compounds used for a bridge or a Reaction agent in the constituent of this invention are denoted by the following formula. R¹_4-zSi[NHCH (R)³)R⁴]_zR' and z are as having described above among a formula, and it is R.³And R⁴Is -- although it is the same or the hydrocarbon group which has 18 carbon atoms from different Noodle 1 is expressed, preferably the number of carbon atoms is from 1 to 10, and it is from 1 to 4 more preferably. R³And R⁴An aralkyl group like a Alkyl machine like Is, methyl, ethyl, propyl, isopropyl, butyl, octyl, Decyl, and octadecyl, an aryl group like phenyl, a trill, an alkaryl group like ethyl phenyl, Ben Jill, and beta-phenylethyl is preferred. The example of a bridge or a Reaction agent denoted by the above-mentioned formula is Silang CH of the following formula.₃Si[NHCH (CH)₃)C₂H₅]₃And the following general formula; inside R and R of a formula¹And g is Silang of , as above-mentioned.<img file="JPH0341108B2_D0003.tif" />A bridge or other silicon compounds which are used for a Reaction agent are inside of an amino Siloxane [ of the following formula ]; type, R', and R.¹,R³,R⁴And m is as above-mentioned and is R.³A Is methyl group, R⁴A Is ethyl group is desirable;. R¹₃SiO (SiR')₂O)_nSi[NHCH (R)³)R⁴]₃The inside of a formula, R', R¹,R³,R⁴And m is the same as the above. R³A Is methyl group is R.⁴A Is ethyl group is preferred. These bridges or a Reaction agent is manufactured, for example by making Halosilane react to a sec-butylamine. The 2nd class butylamine bridges of these, Reaction agents, and those manufacturing processes are indicated in detail in U.S. Pat. No. 3923736, such as Nitzsche raised to this book. Inside of the amine substitution silicon compound of this invention = NCH (R)³)R⁴As for the silicon valence which is not satisfied, in a basis, it is preferred that it is sufficient with a 1 value hydrocarbon group, a halogenation 1 value hydrocarbon group, a cyano Alkyl machine, Si-absorbed water acid radical, and/or the Shiroki Sun oxygen atom. This amine substitution silicon compound is essentially stored under anhydrous conditions, and is added by Shiroki Sunpolymer under essential anhydrous conditions. These amine substitution ORGANO silicon compound is used in quantity that the silicon atom per reactant machine gram this quantity of diorganopolysiloxane and in an amine substitution ORGANO silicon compound serves as at least 1-g this quantity. Generally, 40 weight sections is added from amine substitution ORGANO silicon compound 0.2 per [ containing a reactant machine ] 100 weight sections of organopolysiloxane. It mixes in order of a wish of various ingredients, and the constituent of this invention is manufactured. A deer must be carried out and this mixture must be performed in the atmosphere which does not have water substantially. This constituent can be made to contain the following compression Set (compression-set) additive agents in addition to Shiroki Sunpolymer and an amine substitution ORGANO silicon compound. That is, they are paints, soluble dye, an aromatic series substance (oil refinement), an antioxidant, heat stabilizer, an antiphlogistic and light stabilizer, the reversibility and softener like trimethylsiloxy end blockade dimethylpolysiloxane, a strengthening bulking agent, or an unreinforcement bulking agent. A strengthening bulking agent, i.e., 50 m²Built 2 oxidization silicon, silica aerogel, and sedimentation 2 oxidization silicon are among the examples of the bulking agent which has the surface area more than /g at high temperature with big surface area. An unreinforcement bulking agent, i.e., 50 m²Diatomite, silicic acid calcium, zirconium silicate, what is called molecular sheaves, Chita Near, alumina, iron oxide, a zinc oxide, metal oxide powder, and calcium carbonate are among the examples of the bulking agent which has the surface area below /g. A fibrous restoration thing like asbestos, glass fiber, and an organic fiber can also be used again. As for bulking agents, it is advantageous to process by a publicly known method and to include ORGANO siloxy or an alkoxy group in the surface. The mixture of a different Noodle bulking agent can also be used. As for bulking agents, it is preferred to use it so that it may become 5~90 % of the weight on the basis of organopolysiloxane and the bulking agent total quantity. There is a condensation catalyst which is indicated by United States patent 2843555; 3127363rd and No. 3082527 in the other additive agents used for the constituents of this invention, for example. Although the example of a suitable condensation catalyst is metal salt and ORGANO metal salt of carboxylic acid, this has combination like lead salt of Aliphatic carboxylic acid with 9~11 carbon atoms branched at least by alpha- to the carboxyl group, (lead octoate), and Dibutyltin salt (Dibutyl tin reverse side rate). It is although there is amine in the example, Silang which have at least one piece and at least one 1 value hydrocarbon group for the amino group combined with silicon via 3-ethoxy propylamine 1 and carbon in this, for example Or there is Silang which have the hydrocarbon group which was replaced by one amine machine and/or an alkoxy group, and was combined with silicon via oxygen in each molecule. Latter Silang not only acts as a condensation catalyst, but Then and this are N-beta-(aminoethyl)-gamma-aminopropyl trimethoxysilane, i.e., the compound denoted by a following formula, with the medicine which improves adhesion with an elastomer and a base further again. CH₃Si[O (CH)₂)₂NH₂]₂(CH₂)₃O(CH₂)₂NH₂When using a condensation catalyst, the quantity is a full weight standard of a constituent, and, generally, is 0.01~5 % of the weight, preferably 0.05~1 % of the weight. As long as it is dry, storage with a desired preservation form is possible for this constituent. When it Temperature rising(ed) with the application of this constituent to the base, it found out that adhesion was improvable. That is, although Temperature rising temperature has about 50degreeC to preferred about 180 degreeC, it is most preferred to maintain at about 140 degreeC from about between several to about 30 minutes 100degreeC. The inside of heating, or after heating, this constituent is contacted to the gas-like medium which contained carbon dioxide superfluously so that it might exist in humidity and the atmosphere, and if it is Mustache, it is not. That is, that hardening is promoted by exposing this constituent to the carbon dioxide preferably 0.2 to about 50 capacity %, and the gas-like medium that contained the carbon dioxide of about 0.3 to about 10 capacity % still more preferably of at least 0.1 capacity %. The special advantage was not able to be observed although use of the gas-like medium containing the carbon dioxide more than 50 capacity % was also possible. If this constituent is further exposed to the humidity which exists in the overinside of the bottom atmosphere of pressurization, and the atmosphere of carbon dioxide, the promotion of hardening of the depths will be attained. If it heats to high temperature after contacting this constituent to humidity and carbon dioxide, the surface of an elastomer will serve as inactivity and adhesion will no longer be improved at all. In order to deal in a best result, it is preferred during a heat-treatment period or to contact a constituent to humidity and carbon dioxide after that. By using an amine hardening system with the method of this invention, while pot lives (pot-life) are long and carry out flash set, the adhesion to various bases is improvable. Production can be made to increase by this invention again, without making adhesion poor. Of course, the constituent of this invention can be hardened without Primers (primers) usually used, and can be firmly pasted up on the surface of various bases like glass, porcelain, a china, concrete, mortar, aluminum, a tree, paper, polystyrene, and synthetic resin lacquer. Of course, it is applicable also to the surface which uses a primer. The constituent of this invention is organopolysiloxane for adhesion as the sealing joint in being not only useful as adhesives but a building, a car, a vessel, and an airplane, and an object for an opening blockade. It is useful as adhesives of an elastomer. This is useful also to protection coating and textile coating in the non-adhering finish with which manufacture of a laminated piece is coated of course at paper, an electric insulation, and manufacture of heat interception material. By long pot lives, after applying to Then and a base, this constituent can be used also, for example for a silk screen process, when a constituent that flash set is possible is desired. The following example explains the operation method that this invention is various. As long as there is no special mention, weight has all shown the part. Example 1 The mixture including 100 copies of Hydroxyl group end dimethylpolysiloxane which has the viscosity of 4000cs. by 25 degreeC, and 60 copies of powder quartz and eight copies of methyl tris (sec-butylamino) Silang was applied to various bases in the shape of a 0.0127-cm film in thickness. 1 set of each applied base was contacted into the mixture of air and the carbon dioxide which exists in the overinside of the atmosphere for 4 minutes by 25 degreeC. Another group of the base to which the above-mentioned mixture is applied was contacted into the mixture of the same air and carbon dioxide as the above-mentioned experiment for 4 minutes by 25 degreeC, and was heated for 4 minutes by 110 degreeC after that. Another group of the base to which a mixture is applied similarly was heated for 4 minutes by 110 degreeC in air oven, and the mixture of the same air and carbon dioxide as the above-mentioned experiment was made to contact for 4 minutes by 25 degreeC after that. The degree of adhesion between a base and an elastomer was measured for all the samples after neglect at room temperature for 24 hours in the bottom atmosphere of existence of humidity. This result was shown in the table. Example 2 83 copies of hydroxyl group end dimethylpolysiloxane of viscosity 4000cs. in 25 degreeC, Although the mixture including 17 copies of fumed (fumed) silica bulking agents and ten copies of methyl tris (sec-butylamino) Silang was applied to various bases in the shape of a 0.0127-cm film in thickness and the method given in Example 1 was adopted, it is I got it about intermediary hardening. Those of the elastomer for adhesiveness were shown in the table. Example 3 100 copies of hydroxyl group end dimethylpolysiloxane of viscosity 2000cs. in 25 degreeC, Although the method which applied the mixture including 60 copies of iron oxide and ten copies of methyl tris (sec-butylamino)-Silang to various bases in the shape of a 0.0127-cm film in thickness, and was indicated in the Example 1 was adopted, it is I got it about intermediary hardening. Those of the elastomer for adhesiveness were shown in the table. Example 4 100 copies of hydroxyl group end dimethylpolysiloxane of viscosity 4000cs. in 25 degreeC, Although the method which applied the mixture including 60 copies of iron oxide and eight copies of methyl tris (sec-butylamino)-Silang to various bases in the shape of a 0.0127-cm film in thickness, and was indicated in the Example 1 was adopted, it is I got it about intermediary hardening. Those of the elastomer for adhesiveness were shown in the table. Example 5 100 copies of hydroxyl group end dimethylpolysiloxane of viscosity 450cs. in 25 degreeC, Although the method which applied the mixture including 60 copies of iron oxide and 20 copies of methyl tris (sec-butylamino)-Silang to various bases in the shape of a 0.0127-cm film in thickness, and was indicated in the Example 1 was adopted, it is I got it about intermediary hardening. Those of the elastomer for adhesiveness were shown in the table. Example 6 100 copies of dimethylpolysiloxane of viscosity 4000cs. in 25 degreeC, 20 copies of trimethylsiloxy end dimethylsiloxane of viscosity 50cs. in 25 degreeC, Fumed Mixture containing 12 copies of silica, ten copies of methyl tris (cyclohexylamino) Silang, and 0.5 copy of N-beta-(aminoethyl)-gamma-aminopropyl trimethylsilane, Although the method which was applied to various bases in the shape of a 0.0127-cm film in thickness, and was indicated in the Example 1 was adopted, it is I got it about intermediary hardening. Those of the elastomer for adhesiveness were shown in the table. Example 7 100 copies of hydroxyl group end dimethylpolysiloxane of viscosity 4000cs. in 25 degreeC, The mixture containing 300 copies of zinc oxides, eight copies of methyl tris (cyclohexylamino)-Silang, and 0.5 copy of N-beta-(aminoethyl)-gamma-aminopropyl trimethoxysilane, It is 0.0127 cm in thickness to various bases. Although the method which was applied as the shape of a film and indicated in the Example 1 was adopted, it is I got it about intermediary hardening. Those of the elastomer for adhesiveness were shown in the table. Example 8 (a) Denaturation organopolysiloxane was manufactured by the following method. 92 copies of hydroxyl group end dimethylpolysiloxane, 94 copies of styrene, 77 copies of butyl acrylate, and G t-butyl of viscosity 450cs. in 25 degreeC The mixture of seven copies of peroxide was heated by 130 degreeC among the bottom nitrogen atmosphere of churning for about 4 hours. Next, the unreacted monomer was removed from about 1 mmHg by bottom 120-degreeof decompression C not more than it. (b) 100 copies of denaturation organopolysiloxane, eight copies of methyl tris (sec-butylamino) Silang, and N-beta-(aminoethyl)-gamma which were obtained above (a) - (the mixture of 0.5 copy of aminopropyl trimetoxy-silane was manufactured under anhydrous conditions.) And it is 0.0127 cm in thickness to various bases about this mixture. Although the method which was applied in the shape of a film and indicated in the Example 1 was adopted, it is I got it about intermediary hardening. It was shown in the table for adhesiveness.

[Table]

- Concentrated Defect Good Right lied [Table]

Lied [Table]

* Rubber- asbestos mixture The examining method: Insert a spatula between an elastomer coat and a base and exfoliate a coat from a base. Defect: When a coat exfoliates easily as one. Good: When exfoliation of a coat was difficult, the elastomer split and it remains in small quantities on a base. A: When the elastomer which exfoliation of a coat was very difficult and split mostly remains on a base. Good: The exfoliation situation of a coat is an ON Ivy case between good and A.

[Claim(s)]

1 A Organopolysiloxane Which Has at Least Two Hydroxyl Groups in One Molecule 100 Weight Sections, B) A general formula [A formula]

(R is unsubstituted [ of carbon number 1~8 ], or a substitution univalent saturated hydrocarbon machine here.) An organic Clock matter compound for which 0 or 1b is shown [ a ] by 0, 1 or 2, and a+b+c=4 as for 2 or 3c, or 0.5~30 weight sections of its partial hydrolysate, C) Mercapto group content ORGANO Shiroki Sun which has at least two mercapto groups in [ of quantity from which a mercapto group will be 0.1~20 pieces to the propenyloxy machine 1 piece of B ingredient ] one molecule D) A curing catalyst 0.01~10 weight sections E) increase -- admiration -- an agent -- 0.01~10 weight sections A silicone constituent becoming more.