JP2011236363A - Curable composition comprising (meth)acrylic polymer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To newly provide a curable composition comprising a (meth)acrylic polymer having a reactive silyl group at a terminal, in which a cured product has flexibility and is highly extensible, conventionally not known.SOLUTION: The curable composition comprises both of (A) a (meth)acrylic polymer having reactive silyl groups at both terminals and (B) a (meth)acrylic polymer having a reactive silyl group only at a terminal, in which the component (B) has a weight of not less than 150 pts.wt. and not more than 900 pts.wt. based on the weight of 100 pts.wt. of the component (A).

Description

  The present invention relates to a curable composition, and more particularly to a curable composition containing a (meth) acrylic polymer having a reactive silyl group at the terminal.

  A curable composition mainly composed of an acrylic polymer having a crosslinkable silyl group at the terminal has been proposed (for example, Patent Documents 1 to 4). In JP-B-3-14068 and JP-B-5-72427, a mercaptan chain transfer agent having a crosslinkable silyl group, a disulfide chain transfer agent having a crosslinkable silyl group, and an azo polymerization initiator having a crosslinkable silyl group Although a curable composition based on an acrylic polymer having a crosslinkable silyl group at the end, obtained by using a polymer, has been disclosed, such a production method ensures that the end of the polymer is crosslinkable. It is difficult to introduce a silyl group, and a cured product having satisfactory physical properties cannot be obtained.

  In order to solve this problem, (meth) acrylic polymers having a functional group at the terminal have been developed. In particular, a polymer synthesized using living radical polymerization can arbitrarily control the molecular weight and molecular weight distribution, and can introduce a crosslinkable silyl group quantitatively at the terminal at a low viscosity and at a high ratio. Examples of the vinyl polymer having a crosslinkable silyl group at the terminal include those described in Patent Documents 5 to 11.

  One of the factors affecting the extensibility of a rubber-like cured product obtained by curing a curable composition is the molecular chain length of a crosslinked network structure. That is, it is considered that a highly extensible cured product can be obtained by increasing the molecular weight of the acrylic polymer, but in the conventional method, increasing the molecular weight of the polymer causes an increase in viscosity, which is not realistic. On the other hand, since the living radical polymerization method can obtain a polymer having a lower viscosity than the conventional method, the polymer can have a high molecular weight. By increasing the molecular weight of the polymer, the silyl group concentration can be lowered, and the molecular chain length between silyl groups can be increased. Accordingly, the cured product has a reduced crosslink density consisting of chemical bond points derived from silyl groups and a longer distance between the crosslink points, so that a cured product having a higher elongation than before can be produced.

  However, when the molecular weight of the polymer is increased in order to further increase the elongation, the polymer molecular chains are entangled with each other. If the silyl groups at both ends of the polymer undergo a crosslinking reaction while the molecular chains are entangled with each other, the entanglement is not released at the time of elongation, and the entanglement point also acts as a crosslinking point. As a result, the actual situation is that high elongation sufficient for high molecular weight cannot be obtained. In addition, increasing the viscosity by increasing the molecular weight also reduces workability, so there is a limit to increasing the molecular weight itself.

  On the other hand, a plasticizer, a reactive diluent, etc. can be mix | blended with a curable composition for the purpose of the viscosity reduction of a composition, the softness | flexibility provision to hardened | cured material, and high elongation. For example, polymer plasticizers composed of (meth) acrylic polymers and reactive plasticizers composed of (meth) acrylic polymers are cited as those that do not impair the high weather resistance and high heat resistance of (meth) acrylic polymers. (For example, Patent Document 12). When a plasticizer is blended, an increase in tack due to the migration of the plasticizer to the cured product surface may be a problem. Even when a reactive plasticizer is blended, it is difficult to say that the improvement in elongation is sufficient.

Japanese Examined Patent Publication No. 3-14068 Japanese Patent Publication No. 5-72427 Japanese Patent Publication No. 4-55444 JP-A-6-221922 JP-A-11-201107 Japanese Patent Laid-Open No. 11-80571 Japanese Patent Laid-Open No. 11-116763 JP 2000-38404 A JP 2000-44626 A JP 2000-72815 A JP 2000-72816 A JP 2007-182590 A

  An object of the present invention is to provide a new curable composition containing a (meth) acrylic polymer having a reactive silyl group at the end, the cured product having flexibility and high elongation than ever before. Is to provide.

  As a result of repeated investigations aimed at solving the above problems, the present inventors have (A) a (meth) acrylic polymer having a reactive silyl group at both ends and (B) only reactive at one end. Including both (meth) acrylic polymers having a silyl group, the amount of component (B) is 150 to 900 parts by weight with respect to 100 parts by weight of component (A) It came to complete this invention by setting it as a curable composition.

  That is, a curable composition containing both (A) a (meth) acrylic polymer having a reactive silyl group at both ends and (B) a (meth) acrylic polymer having a reactive silyl group only at one end. And the amount of a component (B) is 150 to 900 weight part with respect to 100 weight part of components (A), It is related with the curable composition characterized by the above-mentioned.

  It is preferable that the (meth) acrylic polymer of component (A) and / or component (B) is produced by a living radical polymerization method.

The amount of the (meth) acrylic polymer having a reactive silyl group only at one end of the component (B) is larger than the (meth) acrylic polymer having a reactive silyl group at both ends of the component (A). (Specifically, 150 parts by weight or more and 900 parts by weight or less) can increase the number of free chain ends in the network structure of the cured product. As a result, the following effects appear.
(1) Since three-dimensional crosslinking points due to silyl groups are reduced, a loose network structure is formed as a whole, and the distance between crosslinking points when viewed macroscopically can be increased.
(2) Since the free chain ends increase, the entanglement between the molecular chains that acted as crosslinking points when the polymer chain is extended is easily unraveled.
Due to these effects, the cured product can be further increased in elongation.

Stress-strain curve of tensile test of the cured product Log-log plot of stress-strain curve of tensile test of the cured product

  The present invention comprises (A) a (meth) acrylic polymer having a reactive silyl group at both ends and (B) a (meth) acrylic polymer having a reactive silyl group only at one end. It is a composition, Comprising: The quantity of a component (B) is 150 to 900 weight part with respect to 100 weight part of components (A), It is a curable composition characterized by the above-mentioned.

As the reactive silyl group, the general formula (1);
_{^{- [Si (R 1) 2}} -b (Y) b O] m -Si (R 2) 3-a (Y) a (1)
{Wherein R ¹ and R ² are all alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 20 carbon atoms, aralkyl groups having 7 to 20 carbon atoms, or (R ′) ₃ SiO— (R 'Is a monovalent hydrocarbon group having 1 to 20 carbon atoms, and three R's may be the same or different), and represents a triorganosiloxy group represented by R ¹ or When two or more R ² are present, they may be the same or different. Y represents a hydroxyl group or a hydrolyzable group, and when two or more Y exist, they may be the same or different. a represents 0, 1, 2, or 3, and b represents 0, 1, or 2. m is an integer of 0-19. However, it shall be satisfied that a + mb ≧ 1. } Is represented.

  Examples of the hydrolyzable group include commonly used groups such as a hydrogen atom, an alkoxy group, an acyloxy group, a ketoximate group, an amino group, an amide group, an aminooxy group, a mercapto group, and an alkenyloxy group. Among these, an alkoxy group, an amide group, and an aminooxy group are preferable, but an alkoxy group is particularly preferable in terms of mild hydrolyzability and easy handling.

  The reactive silyl groups of the component (A) and the component (B) may be the same or different. However, in order to release the entanglement between the molecular chains, it is preferable that the free chain ends exist uniformly as the entire cross-linked structure. It is preferable that there is no significant difference in reactivity.

  The reactive silyl group of component (A) may be present only at both ends, but may be present in the main chain in addition to both ends.

  As the structural unit of the main chain of the (meth) acrylic polymer, various types can be used. For example, (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid-n-propyl, (meth) acrylic acid isopropyl, (meth) acrylic acid-n- Butyl, isobutyl (meth) acrylate, (tert-butyl) (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, (meth) acryl Acid-n-heptyl, (meth) acrylic acid-n-octyl, (meth) acrylic acid-2-ethylhexyl, (meth) acrylic acid nonyl, (meth) acrylic acid decyl, (meth) acrylic acid dodecyl, (meth) Phenyl acrylate, toluyl (meth) acrylate, benzyl (meth) acrylate, 2-methoxyethyl (meth) acrylate (Meth) acrylic acid-3-methoxybutyl, (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, (meth) acrylic acid stearyl, (meth) acrylic acid glycidyl, (meth) 2-aminoethyl acrylate, γ- (methacryloyloxypropyl) trimethoxysilane, ethylene oxide adduct of (meth) acrylic acid, trifluoromethylmethyl (meth) acrylate, 2-trifluoromethylethyl (meth) acrylate , 2-perfluoroethylethyl (meth) acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth) acrylate, 2-perfluoroethyl (meth) acrylate, perfluoromethyl (meth) acrylate , (Perfluoromethylmethyl) (meth) acrylate, (me T) 2-perfluoromethyl-2-perfluoroethylmethyl acrylate, 2-perfluorohexylethyl (meth) acrylate, 2-perfluorodecylethyl (meth) acrylate, 2-perfluoro (meth) acrylate It is a (meth) acrylic acid monomer such as hexadecylethyl.

  These may be used alone or a plurality of these may be copolymerized. Of these, a (meth) acrylic acid ester monomer is preferred from the physical properties of the product, more preferably an acrylic acid ester monomer, and particularly preferably an acrylic acid alkyl ester. In the present invention, these preferable monomers may be copolymerized with other conventionally known monomers, and further block copolymerized. In that case, it is preferable that the (meth) acrylic monomer is contained by 40% or more by weight. In the above expression format, for example, (meth) acrylic acid represents acrylic acid and / or methacrylic acid.

  The number average molecular weight of the (meth) acrylic polymer of component (A) and component (B) is not particularly limited, but is preferably in the range of 500 to 1,000,000, more preferably 1000 to 100,000. The molecular weight distribution (ratio of weight average molecular weight to number average molecular weight) is not particularly limited, but is preferably less than 1.8, preferably 1.7 or less, more preferably 1.6 or less, even more preferably. Is 1.5 or less, particularly preferably 1.4 or less, and most preferably 1.3 or less.

  The number average molecular weight and the weight average molecular weight are determined by a gel permeation chromatography method (GPC method). Usually, chloroform is used as the mobile phase, the measurement is carried out on a polystyrene gel column, and the number average molecular weight and the like can be determined in terms of polystyrene.

  The production method of the (meth) acrylic polymer of component (A) and component (B) is not particularly limited, but from the viewpoint of ease of structure control (molecular weight, molecular weight distribution, terminal functionalization rate, etc.), living polymerization method In particular, the living radical polymerization method is preferred.

  The living radical polymerization method is not particularly limited. For example, atom transfer radical polymerization (ATRP) (J. Am. Chem. Soc. 1995, 117, 5614) or recently proposed by Percec, V et al. Examples include electron transfer living radical polymerization (SET-LRP) (J. Am. Chem. Soc. 2006, 128, 14156, JP Chem Chem 2007, 45, 1607). Both are characterized by living radical polymerization of vinyl monomers using transition metal complexes as polymerization catalysts and organic halides as initiators.

  The reactive silyl group can be introduced into the terminal by a conventionally known method, but it is preferable to use a living radical polymerization method. For example, by using an initiator having a reactive silyl group in living radical polymerization, a method of polymerizing a (meth) acrylic monomer, or using an initiator having a functional group that can be converted to a reactive silyl group (meth) A (meth) acrylic polymer in which a silyl group is introduced into the terminal derived from the initiator can be produced by a method of polymerizing an acrylic monomer and later converting it to a reactive silyl group. Moreover, it is also possible to convert the polymerization growth terminal (preferably halogen terminal) of the (meth) acrylic polymer produced by living radical polymerization into a reactive silyl group. In these methods, if a reactive silyl group is introduced into only one end or both ends, the (meth) acrylic polymer of component (A) or component (B) can be produced. Moreover, the manufacturing method of a general telechelic polymer can also be utilized. Living radical polymerization is performed using a bifunctional initiator, and the (meth) acrylic component (A) is converted by converting a polymerization growth terminal (preferably a halogen terminal) at both ends into a reactive silyl group by a conventionally known method. A polymer is obtained.

In the curable composition comprising (A) a (meth) acrylic polymer having a reactive silyl group at both ends and (B) a (meth) acrylic polymer having a reactive silyl group only at one end, The amount of component (B) is from 150 to 900 parts by weight, preferably from 200 to 700 parts by weight, based on 100 parts by weight of A).
If the amount of the component (B) is too small, the entanglement of the molecular chains is insufficient and the effect of increasing the elongation is weakened. On the other hand, when there is too much quantity of a component (B), it will lead to quality degradation, such as hardening time becoming long or the stickiness by hardening failure becoming strong.

  In the curable composition of the present invention, a curing catalyst or a curing agent may be required. Moreover, you may add various compounding agents according to the target physical property.

  The polymer having a crosslinkable silyl group is crosslinked and cured by forming a siloxane bond in the presence or absence of various conventionally known condensation catalysts. The properties of the cured product can be broadly created from rubbery to resinous depending on the molecular weight and main chain skeleton of the polymer.

  Examples of such a condensation catalyst include dibutyltin dilaurate, dibutyltin diacetate, dibutyltin diethylhexanolate, dibutyltin dioctate, dibutyltin dimethylmalate, dibutyltin diethylmalate, dibutyltin dibutylmalate, dibutyltin diester. Isooctylmalate, dibutyltin ditridecylmalate, dibutyltin dibenzylmalate, dibutyltin maleate, dioctyltin diacetate, dioctyltin distearate, dioctyltin dilaurate, dioctyltin diethylmalate, dioctyltin diisooctylmalate, etc. Tetravalent tin compounds such as: tetrabutyl titanate, tetrapropyl titanate, etc .; aluminum trisacetylacetonate, aluminum trisethylacetoacetate, Organoaluminum compounds such as isopropoxyaluminum ethyl acetoacetate; Chelate compounds such as zirconium tetraacetylacetonate and titanium tetraacetylacetonate; Lead octylate; Butylamine, octylamine, laurylamine, dibutylamine, monoethanolamine, diethanolamine , Triethanolamine, diethylenetriamine, triethylenetetramine, oleylamine, cyclohexylamine, benzylamine, diethylaminopropylamine, xylylenediamine, triethylenediamine, guanidine, diphenylguanidine, 2,4,6-tris (dimethylaminomethyl) phenol, morpholine N-methylmorpholine, 2-ethyl-4-methylimidazole, 1,8-diazabicyclo 5,4,0) undecene-7 (DBU), 1,3-diazabicyclo (5,4,6) undecene-7 and other amine compounds or carboxylates of these amine compounds; laurylamine and tin octylate Reaction product or mixture of amine compound and organotin compound such as reaction product or mixture; low molecular weight polyamide resin obtained from excess polyamine and polybasic acid; reaction product of excess polyamine and epoxy compound; γ -Silanol condensation catalysts such as silane coupling agents having amino groups such as aminopropyltrimethoxysilane and N- (β-aminoethyl) aminopropylmethyldimethoxysilane; and other acidic catalysts, basic catalysts, etc. Examples thereof include silanol condensation catalysts.

  These catalysts may be used alone or in combination of two or more. The amount of the condensation catalyst is preferably about 0.1 to 20 parts by weight, more preferably 1 to 10 parts by weight, based on 100 parts by weight of the vinyl polymer (A1) having at least one crosslinkable silyl group. If the amount of the silanol condensation catalyst is less than this range, the curing rate may be slow, and the curing reaction may not proceed sufficiently. On the other hand, if the blending amount of the silanol condensation catalyst exceeds this range, local heat generation and foaming occur during curing, and it becomes difficult to obtain a good cured product, and the pot life becomes too short, which is preferable from the viewpoint of workability. Absent.

  In order to further increase the activity of the condensation catalyst, a silane compound such as phenyltrimethoxysilane, phenylmethyldimethoxysilane, phenyldimethylmethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, or triphenylmethoxysilane may be blended. In particular, diphenyldimethoxysilane and diphenyldiethoxysilane are most preferable because of low cost and easy availability.

  A silane coupling agent or an adhesion-imparting agent other than the silane coupling agent can be added. Specific examples other than the silane coupling agent are not particularly limited, and examples thereof include epoxy resins, phenol resins, sulfur, alkyl titanates, and aromatic polyisocyanates.

  Furthermore, various fillers are used as necessary. Specific examples of the filler include, for example, wood powder, parb, cotton chips, glass fiber, carbon fiber, mica, walnut shell powder, rice husk powder, graphite, diatomaceous earth, white clay, fumed silica, precipitated silica, Reinforcing fillers such as crystalline silica, fused silica, dolomite, anhydrous silicic acid, hydrous silicic acid, carbon black; calcium carbonate, magnesium carbonate, diatomaceous earth, calcined clay, clay, talc, titanium oxide, bentonite, organic bentonite And fillers such as ferric oxide, aluminum fine powder, flint powder, zinc oxide, activated zinc white, zinc dust and shirasu balloon; and fibrous fillers such as glass fibers and filaments. Further, a filler selected from titanium oxide, calcium carbonate, talc, ferric oxide, zinc oxide, shirasu balloon, and the like can be added.

  Various plasticizers are used in the curable composition of the present invention as necessary. Although it does not specifically limit as a plasticizer, According to the objectives, such as adjustment of a physical property and adjustment of properties, phthalic acid esters, such as dibutyl phthalate, diheptyl phthalate, di (2-ethylhexyl) phthalate, butyl benzyl phthalate, etc .; Dioctyl adipate , Non-aromatic dibasic acid esters such as dioctyl sebacate, dibutyl sebacate, isodecyl succinate; aliphatic esters such as butyl oleate and methyl acetyl ricinolinate; diethylene glycol dibenzoate, triethylene glycol dibenzoate, penta Esters of polyalkylene glycols such as erythritol esters; Phosphate esters such as tricresyl phosphate and tributyl phosphate; Trimellitic acid esters; Chlorinated paraffins; Alkyldiphenyl Partially hydrogenated terphenyl and other hydrocarbon oils; Process oils; Polyethers such as polyethylene glycol and polypropylene glycol; Epoxy plasticizers such as epoxidized soybean oil and epoxy benzyl stearate; Polyester plasticizers, etc. Can be used alone or in admixture of two or more, but is not necessarily required. These plasticizers can also be blended at the time of polymer production.

  You may add the physical property modifier which adjusts the tensile characteristic of the hardened | cured material produced | generated as needed to the curable composition of this invention. Although it does not specifically limit as a physical property regulator, For example, alkyl alkoxysilanes, such as methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, n-propyltrimethoxysilane; dimethyldiisopropenoxysilane, methyltriisopropenoxy Silanes, alkyl isopropenoxy silanes such as γ-glycidoxypropylmethyldiisopropenoxysilane, γ-glycidoxypropylmethyldimethoxysilane, γ-glycidoxypropyltrimethoxysilane, vinyltrimethoxysilane, vinyldimethylmethoxy Silane, γ-aminopropyltrimethoxysilane, N- (β-aminoethyl) aminopropylmethyldimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxy Alkoxysilanes having a functional group such as a silane; silicone varnishes; polysiloxanes and the like.

  A thixotropic agent (anti-sagging agent) may be added to the curable composition of the present invention as necessary to prevent sagging and improve workability. The sagging preventing agent is not particularly limited, and examples thereof include polyamide waxes, hydrogenated castor oil derivatives; metal soaps such as calcium stearate, aluminum stearate, and barium stearate.

  Various additives may be added as necessary for the purpose of adjusting various physical properties of the curable composition or the cured product. Examples of such additives include, for example, flame retardants, curability modifiers, anti-aging agents, radical inhibitors, ultraviolet absorbers, metal deactivators, ozone degradation inhibitors, light stabilizers, phosphorous peroxides. Examples include oxide decomposing agents, lubricants, pigments, foaming agents, and photocurable resins.

  The curable composition of the present invention is not limited, but is a sealing material such as an elastic sealing material for construction and a sealing material for double-glazed glass, and electrical / electronic component materials such as a solar cell back surface sealing material, insulation for electric wires and cables. Electrical insulation materials such as coating materials, adhesives, adhesives, elastic adhesives, paints, powder paints, coating materials, foams, potting agents for electrical and electronic equipment, films, gaskets, casting materials, various molding materials, and It can be used for various applications such as meshed glass, laminated glass end faces (cut parts) for rust prevention and waterproofing, and various damping materials.

  Specific examples of the present invention will be described below together with comparative examples, but the present invention is not limited to the following examples.

In the following Examples, “number average molecular weight” and “molecular weight distribution (ratio of weight average molecular weight to number average molecular weight)” were calculated by a standard polystyrene conversion method using gel permeation chromatography (GPC). However, a GPC column filled with polystyrene cross-linked gel (shodex GPC K-804, shodex GPC K-802.5; manufactured by Showa Denko KK) and chloroform as a GPC solvent were used. The functional group introduced per polymer molecule was subjected to functional group concentration analysis (solvent: deuterated chloroform, measurement temperature: 23 ° C.) by ¹ H-NMR (400 MHz), and calculated from the number average molecular weight determined by GPC.

(Production Example 1) Production Example of Component (A) A specific example of a method for producing poly (n-butyl acrylate) having reactive silyl groups at both ends is shown below.

(1) Polymerization process 100 parts by weight of n-butyl acrylate was deoxygenated. The inside of the stainless steel reaction vessel with a stirrer was deoxygenated, and 0.84 part by weight of cuprous bromide and 20 parts by weight of the deoxygenated n-butyl acrylate were charged and stirred with heating. 8.8 parts by weight of acetonitrile and 1.8 parts by weight of diethyl 2,5-dibromoadipate as an initiator were added and mixed. At the stage where the temperature of the mixture was adjusted to about 80 ° C., pentamethyldiethylenetriamine (hereinafter abbreviated as triamine). ) 0.018 part by weight was added to initiate the polymerization reaction. The remaining 80 parts by weight of n-butyl acrylate was sequentially added to proceed the polymerization reaction. During the polymerization, triamine was appropriately added to adjust the polymerization rate. The total amount of triamine used during the polymerization was 0.15 parts by weight. As the polymerization proceeds, the internal temperature rises due to the heat of polymerization, so the polymerization was allowed to proceed while adjusting the internal temperature to about 80 ° C to about 90 ° C. When the monomer conversion rate (polymerization reaction rate) was about 95% or more, volatile components were removed by devolatilization under reduced pressure to obtain a polymer concentrate.

(2) Diene reaction step 21 parts by weight of 1,7-octadiene (hereinafter abbreviated as diene or octadiene) and 35 parts by weight of acetonitrile were added to the concentrate, and 0.34 part by weight of triamine was added. While adjusting the internal temperature to about 80 ° C. to about 90 ° C., the mixture was heated and stirred for several hours to react the octadiene with the polymer terminal.

(3) Oxygen treatment step When the diene reaction was completed, an oxygen-nitrogen mixed gas was introduced into the gas phase of the reaction vessel. While maintaining the internal temperature at about 80 ° C. to about 90 ° C., the reaction solution was heated and stirred for several hours to bring the polymerization catalyst in the reaction solution into contact with oxygen. Acetonitrile and unreacted octadiene were removed by devolatilization under reduced pressure to obtain a concentrate containing a polymer. The concentrate was markedly colored.

(4) First rough purification step Butyl acetate was used as a diluent solvent for the polymer. The concentrate was diluted with about 100 to 150 parts by weight of butyl acetate with respect to the polymer, a filter aid was added and stirred, and then insoluble catalyst components were removed by filtration. The filtrate was colored by the polymerization catalyst residue and was turbid.

(5) Second rough purification step The filtrate was charged into a stainless steel reaction vessel equipped with a stirrer, and aluminum silicate (KYOWARD 700SEN: manufactured by Kyowa Chemical) and hydrotalcite (KYOWARD 500SH: manufactured by Kyowa Chemical) were added as adsorbents. . After introducing an oxygen-nitrogen mixed gas into the gas phase and heating and stirring at about 100 ° C. for 1 hour, insoluble components such as an adsorbent were removed by filtration. A clear filtrate with coloration was obtained. The filtrate was concentrated to obtain a crude polymer product.

(6) Dehalogenation process (high-temperature heat treatment process) / adsorption purification process Crude polymer, heat stabilizer (Sumilyzer GS: manufactured by Sumitomo Chemical Co., Ltd.), adsorbent (KYOWARD 700SEN, KYOWARD 500SH) Add, raise the temperature while stirring under reduced pressure, heat and agitate, heat and stir for about several hours at a high temperature of about 170 ° C. to about 200 ° C., devaporize under reduced pressure, desorption of halogen groups in the polymer, adsorption purification Carried out. Further adsorbents (Kyoward 700SEN, Kyoward 500SH) were added, about 10 parts by weight of butyl acetate was added to the polymer as a diluting solvent, and the gas phase part was changed to an oxygen-nitrogen mixed gas atmosphere. The mixture was further heated and stirred at a high temperature of 200 ° C. for several hours to continue the adsorption purification. After the adsorption treatment, the polymer was diluted with 90 parts by weight of butyl acetate and filtered to remove the adsorbent. The filtrate was concentrated to obtain a polymer having alkenyl groups at both ends.

(7) Silylation step With respect to 100 parts by weight of the polymer obtained by the above method, 1.7 parts by weight of methyldimethoxysilane (DMS), 0.9 parts by weight of methyl orthoformate (MOF), bis (1,3- Divinyl-1,1,3,3-tetramethyldisiloxane) platinum complex catalyst 0.0010 part by weight of an isopropanol solution was mixed, and heated and stirred at about 100 ° C. After heating and stirring for about 1 hour, volatile components such as unreacted DMS were distilled off under reduced pressure to obtain a polymer [P1] having methoxysilyl groups at both ends.

  [P1] had a number average molecular weight of about 25,000 and a molecular weight distribution of 1.3. The average number of silyl groups introduced per polymer molecule was about 1.9.

(Production Example 2) Production Example of Component (B) Ethyl α-bromobutyrate was used in place of diethyl 2,5-dibromoadipate used in the polymerization step in Production Example 1, and a methoxysilyl group was formed at one end by the same method. A polymer [P2] having was obtained.

  [P2] had a number average molecular weight of about 24,000 and a molecular weight distribution of 1.2. The average number of silyl groups introduced per polymer molecule was about 1.0.

Example 1
For 100 parts by weight of the polymer [P1] obtained in Production Example 1, 233 parts by weight of the polymer [P2] obtained in Production Example 2, 2 parts by weight of tin octylate and 0.5 parts by weight of laurylamine The reactants were added and mixed well, the composition was poured into a mold and degassed under reduced pressure. Heat-cured at 50 ° C. for 20 hours to obtain a sheet-like cured product having rubber elasticity.

  From the resulting cured product, a No. 3 dumbbell-shaped test piece shown in JIS K 7113 was punched out, and mechanical properties were measured by a tensile test (using an autograph manufactured by Shimadzu, measurement temperature: 23 ° C., tensile speed: 200 mm / min) Was measured. The stress-strain curve (SS curve) of the tensile test is shown in FIG. Also, a log-log plot of the stress-strain curve is shown in FIG.

  Moreover, the obtained hardened | cured material was immersed in toluene for 24 hours, the hardened | cured material after toluene extraction was heat-dried, and the gel fraction was measured from the weight change of the hardened | cured material before and behind toluene extraction. The results are shown in Table 2.

(Example 2)
A cured product was produced in the same manner as in Example 1 using the polymer amounts ([P1] and [P2]) shown in Table 1. Moreover, the tensile test of the obtained hardened | cured material and the gel fraction measurement were implemented. The results are shown in FIGS.

(Comparative Examples 1-7)
As Comparative Examples 1 to 7, cured products were prepared in the same manner as in Example 1 using the polymer amounts ([P1] and [P2]) shown in Table 1. Moreover, the tensile test of the obtained hardened | cured material and the gel fraction measurement were implemented. The results are shown in FIGS.

  As shown in FIG. 1, as a result of the tensile test, Examples 1 and 2 exhibited a low modulus and high elongation as compared with Comparative Examples 1-7. Analyzing the log-log plot of the stress-strain curve (FIG. 2), although the ratio of [P1] and [P2] is changed in Comparative Examples 1 to 7 in the deformation region of 10 to 100% elongation. On the other hand, the slopes of the logarithmic plots are almost equal, whereas the slopes of Examples 1 and 2 are small. These examples show that the stress expression mechanism with respect to the elongation is greatly changed compared to the comparative example. That is, in Examples 1 and 2 in which [P2] is excessive, the number of free chain ends in the network structure of the cured product is larger than that in the comparative example, so only three-dimensional crosslinking points due to silyl groups are reduced. In addition, the entanglement points of the molecular chains that acted as crosslinking points are unraveled at the time of elongation, and the number of effective crosslinking points is considerably smaller than that of the comparative example. As a result, a very loose network structure is obtained as a whole, and the cured product can be further increased in elongation.

  Moreover, as shown in Table 2, also in Examples 1 and 2 in which an excessive amount of [P2] is used, a high gel fraction is maintained, and it can be seen that a sufficient form as a cured product is maintained.

Claims (2)

(A) A curable composition containing both a (meth) acrylic polymer having a reactive silyl group at both ends and (B) a (meth) acrylic polymer having a reactive silyl group only at one end. The amount of the component (B) is from 150 parts by weight to 900 parts by weight with respect to 100 parts by weight of the component (A). The curable composition according to claim 1, wherein the component (A) and / or the component (B) (meth) acrylic polymer is produced by a living radical polymerization method.

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