JPH04348117A - Polyorganosiloxane-based graft copolymer - Google Patents

Abstract

PURPOSE:To obtain a polyorganosiloxane-based graft copolymer excellent in impact and weather resistances and low-temperature characteristics and further improved in adhesive strength and bonding strength of films in coating. CONSTITUTION:A polyorganosiloxane-based graft copolymer which is a graft copolymer, prepared by carrying out graft polymerization of one or more vinylic monomers containing at least one epoxy group-containing vinylic monomer with a polyorganosiloxane rubber obtained by copolymerizing 99.8-60wt.% organosiloxane with 0.1-30wt.% cross-linking agent for the polyorganosiloxane rubber and 0.1-10wt.% graft cross-linking agent for the polyorganosiloxane rubber and having a substantial cross-linked structure. The ratio of the component derived from the epoxy group-containing vinylic monomer accounts for 2-30wt.% of the above-mentioned whole copolymer.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides impact resistance, low temperature properties,
This invention relates to a polyorganosiloxane-based graft copolymer that has excellent weather resistance and also has excellent adhesion strength of a coating film during coating.

0002

[Prior Art] A polyorganosiloxane graft copolymer made by graft polymerizing vinyl monomers such as acrylonitrile and styrene to polyorganosiloxane rubber as a thermoplastic resin with excellent impact resistance, low-temperature properties, and weather resistance. Combination is disclosed in JP-A-61-106614.

0003

[Problems to be solved by the present invention] Although this copolymer has excellent impact resistance, low-temperature properties, and weather resistance, organosiloxane oligomer is produced as a by-product during the production of this copolymer, and this oligomer is extremely difficult to remove from
When this copolymer is molded, the oligomer oozes out onto the surface, so when a molded article made from this copolymer is coated, there is a problem in that the adhesion strength of the coating film is low. An object of the present invention is to provide a polyorganosiloxane-based graft copolymer that solves this problem.

0004

[Means for Solving the Problems] In view of the above-mentioned circumstances, the present inventors aimed to obtain a resin that has excellent impact resistance, low-temperature properties, and weather resistance, as well as excellent adhesion of the coating film of painted molded products. As a result of extensive research, we have found that a graft copolymer is a graft copolymer in which one or more vinyl monomers containing at least one epoxy group-containing vinyl monomer are graft-polymerized to a specific polyorganosiloxane rubber. The inventors have discovered that a polyorganosiloxane-based graft copolymer containing a specific proportion of a component derived from a vinyl monomer satisfies all of the above-mentioned properties, and has thus arrived at the present invention. Furthermore, such polyorganosiloxane-based graft copolymers are also useful as adhesives, and are particularly effective when laminating polyesters such as polyethylene terephthalate, and aromatic polymers such as polyphenylene oxide and polyphenylene sulfide. It exhibits excellent adhesive performance.

That is, the present invention provides organosiloxane 99.
A polyorganosiloxane having a substantially crosslinked structure obtained by copolymerizing 8 to 60% by weight of a crosslinking agent for polyorganosiloxane rubber, 0.1 to 30% by weight of a crosslinking agent for polyorganosiloxane, and 0.1 to 10% by weight of a graft crosslinking agent for polyorganosiloxane. A graft copolymer obtained by graft-polymerizing rubber with one or more vinyl monomers containing at least one epoxy group-containing vinyl monomer, wherein the epoxy group-containing vinyl monomer accounts for the entire copolymer. The present invention is a polyorganosiloxane-based graft copolymer characterized in that the proportion of components derived from polymers is 2 to 30% by weight.

The polyorganosiloxane rubber constituting the graft copolymer of the present invention can be obtained in the form of crosslinked fine particles by emulsion polymerization of organosiloxane, a crosslinking agent, and a graft crosslinking agent. In producing the latex of this polyorganosiloxane rubber component, for example, U.S. Pat.
The method described in Specification No. 5 etc. can be used. In carrying out the present invention, a mixed solution of an organosiloxane, a crosslinking agent, and a grafting agent is shear mixed with water using, for example, a homogenizer in the presence of a sulfonic acid emulsifier such as an alkylbenzenesulfonic acid or an alkylsulfonic acid. It is preferable to manufacture by a method of. As the sulfonic acid emulsifier, alkylbenzenesulfonic acid is preferably used because it acts as an emulsifier for organosiloxane and also as a polymerization initiator. At this time, if alkylbenzenesulfonic acid metal salts, alkylsulfonic acid metal salts, etc. are used in combination, the polymer will
It is preferable because it is effective in stably maintaining the emulsified state of.

[0007] The organosiloxane used for preparing the polyorganosiloxane rubber is preferably a cyclic organosiloxane having three or more membered rings, and particularly preferably one having three to six membered rings. Examples of such cyclic organosiloxanes include hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, and octaphenyl. Examples include cyclotetrasiloxane. The polyorganosiloxane rubber in the present invention is preferably one in which the component derived from a cyclic organosiloxane has repeating units of dimethylsiloxane.

[0008] As a crosslinking agent for polyorganosiloxane rubber used in the preparation of polyorganosiloxane rubber,
Trifunctional or tetrafunctional ones, ie trialkoxyalkyl or arylsilanes or tetraalkoxysilanes, are used; specific examples of such crosslinking agents include trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane, Examples include tetraethoxysilane, tetra-n-propoxysilane, and tetrabutoxysilane. As the crosslinking agent used in the present invention, tetraalkoxysilane is preferable, and among the above, tetraethoxysilane is particularly preferably used.

The grafting agent used in the preparation of polyorganosiloxane rubber is expressed by the following formula:

0010

[Chemical formula 1]

[0011]

[Case 2]

0012

[Chemical formula 3]

[0013]

[C4]

(In each formula, R1 represents a methyl group, ethyl group, propyl group or phenyl group, R2 represents a hydrogen atom or a methyl group, n represents 0, 1 or 2, and p represents 1 to 2.
Indicates an integer of 6. ) are used.

[0015] A unit represented by formula 1 can be formed (meta)
Since acryloyloxyalkylsiloxane has a high grafting efficiency, it is possible to form graft chains efficiently and is advantageous in terms of impact resistance. Among the (meth)acryloyloxyalkylsiloxanes, methacryloyloxyalkylsiloxanes are preferred, and specific examples thereof include β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, and γ-methacryloyloxypropyldimethoxymethylsilane. Examples include methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropylethoxydiethoxysilane, γ-methacryloyloxypropyldiethoxymethylsilane, and δ-methacryloyloxybutyldiethoxymethylsilane.

Examples of the vinylsiloxane that can form the unit represented by formula 2 include vinylmethyldimethoxysilane and vinyltrimethoxysilane, and examples of the mercaptosiloxane that can form the unit represented by formula 3 include γ-mercapto. Examples include propyldimethoxymethylsilane, γ-mercaptopropyltrimethoxysilane, and γ-mercaptopropyldiethoxyethylsilane. Furthermore, examples of the grafting agent capable of forming the unit represented by Chemical Formula 4 include p-vinylphenylmethyldimethoxysilane. A compound capable of forming a unit in which n is 0 in each of formulas 1 to 4 also acts as a crosslinking agent.

In the polyorganosiloxane rubber, the amount of the component derived from the cyclic organosiloxane is 60% by weight or more, preferably 70% by weight or more, and the amount of the component derived from the crosslinking agent is 0.1 to 30% by weight, The amount of components derived from the grafting cross-agent is 0.1-10% by weight. If the amount of the crosslinking agent used is less than 0.1% by weight, it will be difficult to form a substantial crosslinked structure, and the impact resistance of the molded product made from the resulting copolymer will decrease; The amount used does not increase the amount of available crosslinking structure. If the amount of the graft cross-agent used is less than 0.1% by weight, effective graft chains will not be formed during the subsequent graft polymerization, resulting in poor dispersion of the polyorganosiloxane rubber particles in the copolymer.
If an amount exceeding % by weight is used, a reaction between the graft cross-agents will occur during graft polymerization, and in either case, impact resistance may decrease and the purpose of the present invention may be impaired.

The polyorganosiloxane rubber thus obtained can be graft copolymerized with a vinyl monomer. The polyorganosiloxane graft copolymer used in the present invention is obtained by graft polymerizing this polyorganosiloxane rubber with one or more vinyl monomers including at least one epoxy group-containing vinyl monomer. Yes, if the component derived from the epoxy group-containing vinyl monomer is contained in the graft copolymer in an amount of 2 to 30% by weight, the monomer and the epoxy group-containing vinyl monomer can be combined together. A copolymerizable vinyl monomer may be graft-polymerized.

As the epoxy group-containing vinyl monomer,
glycidyl methacrylate, glycidyl acrylate,
Examples include vinyl glycidyl ether, allyl glycidyl ether, glycidyl ether of hydroxyalkyl (meth)acrylate, glycidyl ether of polyalkylene glycol (meth)acrylate, and glycidyl itaconate. These can be used alone or in combination of two or more. Among these, use of glycidyl methacrylate is more preferred.

Examples of the vinyl monomer copolymerizable with the epoxy group-containing vinyl monomer include methyl methacrylate,
Methacrylic acid esters such as 2-ethylhexyl methacrylate; Acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate; Styrene,
Examples include aromatic alkenyl compounds such as halogen-substituted styrene, α-methylstyrene, and vinyltoluene; vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; these may be used alone or in combination of two or more.

The proportion of the component derived from the grafted vinyl monomer in the graft copolymer is preferably 5 to 95%, and 10 to 90%, based on the weight of the graft copolymer as 100%. More preferably it is % by weight.

Further, the polyorganosiloxane graft copolymer of the present invention has a latex having an average particle diameter of 0.
．． The average particle size is preferably in the range of 0.08 to 0.6 μm; if the average particle size is smaller than 0.08 μm, it will be difficult to obtain sufficient impact strength, and if it is larger than 0.6 μm, molding from the resulting copolymer will be difficult. The surface appearance of the product may deteriorate. The polyorganosiloxane-based graft copolymer having such an average particle size is produced by adding one or more monomers containing at least one epoxy group-containing vinyl monomer in the presence of the above-mentioned polyorganosiloxane rubber latex. It can be obtained by single-stage or multi-stage emulsion graft polymerization. In addition, if a monomer other than the epoxy group-containing vinyl monomer is also used as one or more monomers containing the epoxy group-containing vinyl monomer and graft polymerization is carried out in multiple stages, the epoxy group is added in the final stage. It is preferable to add a vinyl monomer.

[0023] In the graft polymerization, components corresponding to branches of the graft copolymer (herein, components derived from one or more monomers including an epoxy group-containing vinyl monomer) are used as backbone components (herein, polyorganic monomers). A so-called free polymer obtained by polymerizing only branch components without grafting onto a siloxane rubber (siloxane rubber) is also produced as a by-product, and is obtained as a mixture of a graft copolymer and a free polymer, but in the present invention, both of these are used. Together they are called graft copolymers.

The polyorganosiloxane graft copolymer of the present invention has excellent impact resistance, low-temperature properties, and weather resistance, and when it is molded and painted, it becomes a molded product with excellent coating film adhesion. It is also useful as an adhesive and can be used to bond metals such as aluminum, wood, paper, glass, etc., and various structural laminate products, and is especially useful for bonding aromatic polymer molded products. Useful as a melt adhesive.

Examples of the aromatic polymer include polyethylene terephthalate, polybutylene terephthalate, polyethylene terephthalate isophthalate, polyethylene-2,6-naphthalene dicarboxylate, and polyphenylene terephthalate. Examples include aromatic polyesters such as bisphenol A/terephthalic acid polycondensate, bisphenol A/terephthalic acid isophthalic acid copolycondensate, substituted or unsubstituted polyphenylene oxide, and polyphenylene sulfide. Among these, polyethylene terephthalate, polybutylene terephthalate, substituted or unsubstituted polyphenylene oxide, and polyphenylene sulfide can be mentioned as preferred adhesive materials for use with the graft copolymer of the present invention.

[0026]

EXAMPLES The present invention will be explained in more detail below using examples. In addition, in each example and comparative example, "part" and "
%" means parts by weight or weight % unless otherwise specified. In addition, the adhesion of the paint film was determined by forming a flat plate, applying acrylic urethane paint to its surface, and after drying, making 100 cross-cuts by making 11 vertical and horizontal cuts on the painted surface at 1 mm intervals. A cellophane adhesive tape was attached to the surface of the sample, and the adhesion of the coating film was evaluated based on the number of peeled coating layers when the tape was peeled off in the vertical direction. And the number of peeled paint films is
20 sheets or less: ○, 21 to 40 sheets: △, 41
Those with more than one sheet were marked as ×.

Izod impact strength was measured according to ASTM D 256 using 1/4" notched specimens. Weather resistance was measured at 1000 in a Sunshine Weathermeter.
After time exposure, visually evaluate the change in color tone. No change: ○, slightly yellowed: △, yellowed: ×
And so. The average particle diameter was measured using the quasi-elastic light scattering method (MALVER).
Latex diluted with water was measured as a sample solution using N SYSTEM 4600, measurement speed 25° C., scattering angle 90° C.).

Example 1 2 parts of tetraethoxysilane, 0.5 part of γ-methacryloyloxypropyldimethoxymethylsilane and 97.5 parts of octamethylcyclotetrasiloxane were mixed to obtain 100 parts of a siloxane mixture. Add 100 parts of the above mixed siloxane to 200 parts of distilled water in which 1 part each of sodium dodecylbenzenesulfonate and dodecylbenzenesulfonic acid have been dissolved, and add 100 parts of the above mixed siloxane to 10,000 parts using a homomixer.
After pre-stirring at 0 rpm, use a homogenizer for 30 min.
Emulsification was performed at a pressure of 0 kg/cm2 to obtain organosiloxane latex. This latex was transferred to a separable flask equipped with a condenser and stirring blades, heated at 80°C for 5 hours while stirring and mixed, and then left at 20°C for 48 hours.Then, the pH of this latex was adjusted to 7 with an aqueous sodium hydroxide solution. Polymerization is completed by neutralizing to .0,
A polyorganosiloxane latex (referred to as polyorganosiloxane latex-1) was obtained. The conversion rate to the obtained polyorganosiloxane rubber was 89.7%.

[0029] This polyorganosiloxane latex
1 was taken, 267 parts of distilled water and 0.5 part of sodium dodecylbenzenesulfonate were added thereto, and further 10 parts of glycidyl methacrylate and 24 parts of acrylonitrile were added.
parts, 56 parts of styrene and tert-butylhydroper
Add a mixed solution of 0.216 parts of oxide, and further add a mixed solution of 0.001 part of ferrous sulfate, 0.003 parts of ethylenediaminetetraacetic acid disodium salt, 0.108 parts of Rongalit and 10 parts of distilled water, Radical polymerization was performed. Thereafter, the internal temperature was maintained at 70° C. for 4 hours to complete the graft polymerization to the polyorganosiloxane rubber. The polymerization rate of glycidyl methacrylate, acrylonitrile and styrene was 96.3%, and the average particle size of the graft polymer latex was 0.21 μm. The obtained graft copolymer latex was coagulated with an aqueous calcium chloride solution, filtered and dried to obtain a dry powder of a polyorganosiloxane graft copolymer (hereinafter referred to as S-1).

[0030] After extruding S-1 into pellets using an extruder with a barrel temperature of 230°C, an injection molding machine (Toshiba Machine Co., Ltd.)
A flat plate of 100×100×3 mm was prepared using a cylinder temperature of 230° C. and a mold temperature of 60° C. The surfaces of these flat plates were degreased with methanol and painted with acrylic-urethane paint, and a peeling test of the paint film was conducted. In addition, test pieces for impact strength evaluation were molded under similar injection conditions, and impact resistance was evaluated. The results are shown in Table 1.

Example 2 99 parts of polyorganosiloxane latex-1 obtained in the same manner as in Example 1 was collected, and 218 parts of distilled water was added to it.
Add 0.5 parts of sodium dodecylbenzenesulfonate, and prepare a mixture of 10 parts of glycidyl methacrylate, 18 parts of acrylonitrile, 42 parts of styrene, and 0.216 parts of tert-butyl hydroperoxide, and combine these ingredients to form polyorganosiloxane rubber. penetrate into the particles,
Furthermore, a mixed solution of 0.001 part of ferrous sulfate, 0.003 part of ethylenediaminetetraacetic acid sodium salt, 0.108 part of Rongalit and 10 parts of distilled water was added to carry out graft polymerization onto the polyorganosiloxane rubber. After that, the internal temperature was 70℃.
The mixture was held for 4 hours to complete the graft polymerization, and a latex of a polyorganosiloxane graft copolymer (hereinafter referred to as S-2) was obtained. This was coagulated with an aqueous calcium chloride solution, filtered, and dried to obtain a graft copolymer as a dry powder. This was evaluated in the same manner as in Example 1. The results are shown in Table 1. The polymerization rate of glycidyl methacrylate, acrylonitrile, and styrene was 96.3%, and the average particle size of the graft copolymer latex was 0.20 μm.

Example 3 10 parts of glycidyl methacrylate, 1 part of acrylonitrile
A polyorganosiloxane-based graft copolymer (hereinafter referred to as S-3 ) was obtained. The polymerization rate of glycidyl methacrylate, acrylonitrile, and styrene was 96.7%, and the average particle size of the graft copolymer latex was 0.20 μm. This was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Example 4 10 parts of tetraethoxysilane as a siloxane mixture,
A polyorganosiloxane latex (hereinafter referred to as polyorganosiloxane latex-2) was obtained in the same manner as in Example 1, except for using 100 parts of a mixture of 5 parts of γ-methacryloyloxypropyldimethoxymethylsilane and 85 parts of octamethylcyclotetrasiloxane. Ta. The conversion rate to organosiloxane rubber was 90.1%. Graft polymerization was carried out under the same operations and conditions as in Example 1 except for using this polyorganosiloxane latex-2, and a polyorganosiloxane-based graft copolymer (hereinafter referred to as S
-4) was obtained. The polymerization rate of glycidyl methacrylate, acrylonitrile, and styrene was 97.0%, and the average particle size of the graft copolymer latex was 0.20 μm. Table 1 shows the results of evaluating S-4 in the same manner as in Example 1.

Comparative Example 1 Glycidyl methacrylate 10 was used as a monomer composition to be graft-polymerized to polyorganosiloxane latex-1.
A polyorganosiloxane-based graft copolymer (hereinafter referred to as S-5) was prepared in the same manner as in Example 1, except that a mixture of 27 parts of acrylonitrile and 63 parts of styrene was used instead of 24 parts of acrylonitrile and 56 parts of styrene. Obtained. The polymerization rate of acrylonitrile and styrene is 97.0%,
The average particle size of the graft copolymer latex is 0.20 μm
Met. Table 1 shows the results of evaluating S-5 in the same manner as in Example 1.

Comparative Example 2 A polyorganosiloxane latex (hereinafter referred to as polyorganosiloxane) was prepared in the same manner as in Example 1, except that 100 parts of a mixture of 2 parts of γ-methacryloyloxypropyldimethoxymethylsilane and 98 parts of octamethylcyclotetrasiloxane was used as the siloxane mixture. Siloxane latex-3) was obtained, and graft polymerization was carried out in the same manner as in Example 1 to obtain a polyorganosiloxane graft copolymer (referred to as siloxane latex-3).
(hereinafter referred to as S-6) was obtained. The conversion rate to organosiloxane rubber was 89.2%, glycidyl methacrylate,
The polymerization rate of acrylonitrile and styrene was 97.2%, and the average particle size of the graft copolymer latex was 0.19 μm. Table 1 shows the results of evaluating S-6 in the same manner as in Example 1.

[0036]

[Table 1]

In Table 1, PDMS is polyorganosiloxane rubber, GMA is glycidyl methacrylate, and A
N represents acrylonitrile, and St represents styrene.

Example 5 300 parts of polyorganosiloxane rubber latex-1 obtained in accordance with Example 1 was taken, and a mixed solution of 10 parts of glycidyl methacrylate and 0.024 parts of tert-butyl hydroperoxide was added thereto. Drop it over 30 minutes and bring the internal temperature to 7.
Graft polymerization was carried out by holding at 0°C for 4 hours to obtain a latex of polyorganosiloxane-based graft copolymer (hereinafter referred to as S-7), which was coagulated with an aqueous calcium chloride solution and filtered. 7 dry powder was obtained. The polymerization rate of glycidyl methacrylate was 98.5%, and the average particle size of the graft copolymer latex was 0.20 μm.

This S-7 was sandwiched between two polyethylene terephthalate films (manufactured by Toray Industries, Inc., trade name: Mylar, film thickness 100 μm), and heated at 200° C. at 10 kg/cm 2
A three-layer sheet with an intermediate layer of 20 μm was formed by thermocompression bonding for 10 minutes.
created a list. A test piece with a width of 10 mm was cut from this sheet, and the interlayer adhesive strength was measured by peeling it 180 degrees at 23°C and 0°C. The results are shown in Table 2.

Comparative Example 3 300 parts of polyorganosiloxane latex-1 was collected in the same manner as in Example 1, a mixed solution of 10 parts of methyl methacrylate and 0.024 parts of tert-butyl hydroperoxide was added, and the internal temperature was Graft polymerization was carried out by holding at 70°C for 4 hours. The polymerization rate of methyl methacrylate is 98.
8%, the average particle size of the graft copolymer latex is 0.2
It was 0 μm. The obtained latex was coagulated with an aqueous calcium chloride solution and dried by filtration to obtain a polyorganosiloxane-based graft copolymer (referred to as S-8) as a dry powder. This was evaluated in the same manner as in Example 5, and the results are shown in Table 2.

Comparative Example 4 Ethylene-glycidyl methacrylate copolymer (manufactured by Sumitomo Chemical Co., Ltd., Bond Fast-E) was used as an adhesive.
), a three-layer laminated sheet was prepared in the same manner as in Example 5, and evaluated. The results are shown in Table 2.

[0042]

[Table 2]

[0043] In Table 2, BF-E is bond first.
Indicates E. In addition, preferred embodiments of the present invention are shown below. (1) The polyorganosiloxane-based graft copolymer according to claim 1, wherein the polyorganosiloxane rubber contains polydimethylsiloxane as a main component. (2) The polyorganosiloxane graft copolymer according to claim 1, wherein the epoxy group-containing vinyl monomer is glycidyl (meth)acrylate. (3) The polyorganosiloxane graft copolymer according to claim 1, wherein the epoxy group-containing vinyl monomer is glycidyl methacrylate.

(4) The proportion of one or more vinyl monomers including at least one epoxy group-containing vinyl monomer to be grafted to the polyorganosiloxane rubber is based on the entire polyorganosiloxane graft copolymer. 10-9
The polyorganosiloxane graft copolymer according to claim 1, which has a content of 0% by weight. (5) The polyorganosiloxane-based graft copolymer according to claim 1, wherein the crosslinking agent used for preparing the polyorganosiloxane rubber is tetraalkoxysilane. (6) The polyorganosiloxane-based graft copolymer according to claim 1, wherein the graft cross-agent used in the preparation of the polyorganosiloxane rubber is methacryloyloxysiloxane.

[0045]

[Effect of the invention] According to the present invention, impact resistance, low temperature properties,
A polyorganosiloxane-based graft copolymer with excellent weather resistance and excellent adhesion strength of the coating film during painting is obtained.
The copolymers are also useful as adhesives, particularly in making laminates from polyester and the like.

Claims (1)

[Claims] Claim 1: Organosiloxane 99.8-60% by weight
and 0.1 to 30% by weight of a crosslinking agent for polyorganosiloxane rubber and 0.1% of a graft crosslinking agent for polyorganosiloxane.
A graft copolymer in which one or more vinyl monomers containing at least one epoxy group-containing vinyl monomer are graft-polymerized to a polyorganosiloxane rubber having a substantially crosslinked structure copolymerized with ~10% by weight. 1. A polyorganosiloxane graft copolymer, characterized in that the proportion of a component derived from an epoxy group-containing vinyl monomer in the entire copolymer is 2 to 30% by weight.