JPH07206951A - Graft copolymer and resin composition - Google Patents

Abstract

PURPOSE:To obtain a composite rubber-based graft copolymer useful for molded products excellent in impact resistance and processability, made by graft polymerizing vinyl monomers on a specific composite rubber and having a given number average particle size. CONSTITUTION:This composite rubber-based graft copolymer comprising (A) a composite rubber consisting of a polyorganosiloxane component such as hexamethylcyclotrisiloxane, etc., and an alkyl (meth)acrylate component consisting of an alkyl (meth)acrylate such as methyl acrylate, etc., and a polyfunctional alkyl (meth)acrylate such as allyl methacrylate and having 40-70 swelling degree and (B) one or >=2 vinyl monomers grafted onto the composite rubber, having 0.005-0.08mum average particle size and <=20% volume of >0.10mum particle size against the total volume of the particles. Here, a resin composition can be obtained from 1-20wt.% composite rubber based graft copolymer and 99-70% vinyl chloride resin.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impact resistant resin having excellent impact resistance and workability.

[0002]

2. Description of the Related Art Various efforts have been made so far to improve the performance of impact resistant resins. For example, JP-A-61-1
In Japanese Patent No. 38654, attention is paid to a decrease in Tg and elastic modulus of a rubber layer, and it is considered to use a polyorganosiloxane rubber having both a low Tg and a low elastic modulus as a rubber source of an impact resistant resin. However, this method has a problem that the fluidity due to the polyorganosiloxane rubber is lowered. Further, when such a rubber is used, the impact resistance is lowered if the particle size is small, and therefore a large particle size is used, and thus the surface gloss is also poor.

In Japanese Patent Laid-Open No. 63-69859, a vinyl monomer is graft-polymerized on a composite rubber composed of a polyorganosiloxane rubber and a poly (meth) acrylic rubber in order to improve the surface appearance of a resin molded product. There has been proposed a composite rubber-based graft copolymer.

[0004]

However, when the composite rubber graft copolymer disclosed in JP-A-63-69859 is used as the rubber component of the impact resistant resin, the particle diameter of the rubber component is The workability is not improved because it is larger than 0.08 μm and the degree of rubber crosslinking is high. Therefore, it has been strongly desired to develop an impact resistant resin having good impact resistance and excellent workability.

[0005]

Means for Solving the Problems The inventors of the present invention have diligently studied the relationship between the particle size and the degree of crosslinking of the graft copolymer and the impact resistance and processability. As a result, polyorganosiloxane having a minute particle size was selected. By using it to produce a composite rubber composed of a polyorganosiloxane and a poly (meth) acrylate having a fine particle diameter and a swelling degree in a specific range,
The present inventors have found that the graft copolymer obtained from this composite rubber exhibits excellent impact resistance and, at the same time, good processability.

That is, the first gist of the present invention consists of (A) a polyorganosiloxane component and an alkyl (meth) acrylate component composed of an alkyl (meth) acrylate and a polyfunctional alkyl (meth) acrylate. The number average particle diameter obtained by graft-polymerizing one or two or more vinyl-based monomers to the composite rubber having a swelling degree in toluene of 40 to 70 is 0.005 to 0.0.
A composite rubber-based graft copolymer having a volume of particles of 8 μm and larger than 0.10 μm is 20% or less of the total particle volume, and the second gist is the above-mentioned composite rubber-based graft copolymer (A ) 1 to 30% by weight and (B) a vinyl chloride resin 99 to 70% by weight.

The composite rubber-based graft copolymer (A) of the present invention has a number average particle size in the range of 0.005 to 0.08 μm, and the weight of particles larger than 0.1 μm is the weight of all graft composite rubber particles. Is 20% or less. When the number average particle diameter is smaller than 0.005 μm, the impact resistance of the molded product of the composite rubber-based graft copolymer deteriorates.
If the number average particle diameter is larger than 0.08 μm, the fluidity is lowered and the workability is deteriorated.

The amount of the composite rubber graft copolymer in the resin composition of the present invention is 1 to 30% by weight, preferably 1 to 15% by weight.

When the amount is less than 1% by weight, the impact strength is not remarkably expressed, and when the amount exceeds 30% by weight, the composite rubber-based graft copolymer is bled out to the surface of the molded product, so that the surface gloss of the molded product is increased. Is reduced. Further, since the viscosity of the composition increases, the processability also decreases.

The polyorganosiloxane used in the present invention is a latex prepared by emulsifying an organosiloxane mixture composed of a diorganosiloxane and optionally a siloxane crosslinking agent and a siloxane graft crossing agent with an emulsifier and water at high speed. After homogenizing using a homomixer that atomizes by shearing force with a homogenizer or a homogenizer that atomizes by jetting pressure from a high-pressure generator, it is added dropwise to a hot dodecylbenzenesulfonic acid aqueous solution at a constant rate to polymerize. , Then can be obtained by neutralizing dodecylbenzene sulfonic acid with an alkaline substance.

Examples of the organosiloxane that constitutes the organosiloxane mixture include various organosiloxane cyclic compounds having three or more membered rings, and those having 3 to 6 membered rings are preferable. Specifically, hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane, dodecamethylcyclohexasiloxane, trimethyltriphenylcyclotrisiloxane, tetramethyltetraphenylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, etc. These may be used alone or in admixture of two or more. The amount of these used is 50% by weight or more, preferably 70% by weight or more, and more preferably 90% by weight in the organosiloxane mixture.

As the siloxane-based crosslinking agent, a trifunctional or tetrafunctional silane-based crosslinking agent such as trimethoxymethylsilane, triethoxyphenylsilane, tetramethoxysilane, tetraethoxysilane, tetra-n-propoxysilane, tetra Butoxysilane or the like is used.
In particular, a tetrafunctional crosslinking agent is preferable, and among these, tetraethoxysilane is most preferable. The amount of the cross-linking agent used is 0 to 10% by weight, preferably 0 to 5% by weight in the organosiloxane mixture.

As the siloxane-based graft crossing agent, compounds capable of forming a unit represented by the following formula are used.

CH ₂ = C (R ² ) -COO- (CH ₂ ) _{p
^{-SiR 1 n O (3-n}} ) / 2 - (I-1) CH 2 = CH-SiR 1 n O (3-n) / 2 - (I-2) HS- (CH 2) p -SiR 1 _n O _{(3-n) / 2-} (I-
3) In the above formula, R1 is a methyl group, ethyl group, propyl group or phenyl group, R2 is a hydrogen atom or a methyl group,
n is 0, 1 or 2, and p is a number of 1 to 6.

The (meta) which can form the unit of formula (I-1)
Acryloyloxysiloxane has a high grafting efficiency and thus can form an effective graft chain, and is advantageous in that it exhibits impact resistance.

Methacryloyloxysiloxane is particularly preferred as a unit capable of forming the unit of the formula (I-1). Specific examples of methacryloyloxysiloxane include β-methacryloyloxyethyldimethoxymethylsilane, γ-methacryloyloxypropylmethoxydimethylsilane, γ-methacryloyloxypropyldimethoxymethylsilane, γ-methacryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyl. Examples thereof include ethoxydiethylsilane, γ-methacryloyloxypropyldiethoxymethylsilane, and δ-methacryloyloxybutyldiethoxymethylsilane.

Vinyl siloxane may be mentioned as a unit capable of forming the unit of the formula (I-2), and a specific example thereof is tetramethyltetravinylcyclotetrasiloxane,
Examples of the unit capable of forming the unit of the formula (I-3) include γ-mercaptopropyldimethoxymethylsilane, γ-mercaptopropylmethoxydimethylsilane and γ-mercaptopropyldiethoxymethylsilane.

The amount of the graft crossing agent used in the organosiloxane mixture is 0 to 10% by weight, preferably 0.5 to 5% by weight.

As the emulsifier, anionic emulsifiers are preferable, and sodium alkylbenzene sulfonate, sodium lauryl sulfonate, sodium sulfosuccinate,
An emulsifier selected from sodium polyoxyethylene nonylphenyl ether sulfate and the like is used. Particularly, sulfonic acid-based emulsifiers such as sodium alkylbenzene sulfonate and sodium lauryl sulfonate are preferable.

These emulsifiers are used in the range of 0.1 to 30 parts based on 100 parts of the organosiloxane mixture. If it is less than 0.1 part, the dispersed state becomes unstable, and the emulsified state of a fine particle size cannot be maintained. On the other hand, if the amount exceeds 30 parts, the coloring of the obtained polyorganosiloxane due to the emulsifier becomes severe.

A composite rubber can be obtained by polymerizing the polyorganosiloxane latex thus produced with an alkyl (meth) acrylate component composed of an alkyl (meth) acrylate and a polyfunctional alkyl (meth) acrylate. .

As the alkyl (meth) acrylate,
For example, methyl acrylate, ethyl acrylate, n-
Propyl acrylate, n-butyl acrylate, 2-
Examples thereof include alkyl acrylates such as ethylhexyl acrylate and hexyl methacrylate, 2-ethylhexyl methacrylate, alkyl methacrylates such as n-lauryl methacrylate, and the use of n-butyl acrylate is particularly preferable.

Examples of polyfunctional alkyl (meth) acrylates include allyl methacrylate, ethylene glycol dimethacrylate, propylene glycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,4-butylene glycol dimethacrylate, triallyl cyanurate. , Triallyl isocyanurate and the like.

The amount of the polyfunctional alkyl (meth) acrylate used is 0.0 in the alkyl (meth) acrylate component.
2 to less than 2.0% by weight, preferably 0.05 to less than 1.0% by weight.

The above alkyl (meth) acrylate component is added to the latex of the neutralized polyorganosiloxane component, and a normal radical polymerization initiator is allowed to act to polymerize. As the polymerization initiator, a peroxide, an azo initiator, or a redox initiator in which an oxidizing agent and a reducing agent are combined is used. Among these, a redox type initiator is preferable, and a sulfoxylate type initiator in which ferrous sulfate, ethylenediaminetetraacetic acid disodium salt, Rongalite, and hydroperoxide are combined is particularly preferable.

As the polymerization proceeds, polyalkyl (meth) s entwined with each other in the crosslinked network of the polyorganosiloxane component
A crosslinked network of the acrylate component is further finely formed, and a latex of a composite rubber of a polyorganosiloxane component and a polyalkyl (meth) acrylate component which cannot be separated substantially is obtained.

In the composite rubber composed of polyorganosiloxane and polyalkyl (meth) acrylate according to the present invention, the polyorganosiloxane component is 1.0 to 7
It is about 0% by weight. If it is less than 1.0% by weight, the characteristics of polyorganosiloxane cannot be exhibited and the impact resistance is lowered. On the other hand, if it exceeds 70% by weight, the compatibility with PVC is lowered and the surface appearance is deteriorated. The swelling degree of the composite rubber is preferably 40 to 70. If the degree of swelling is 40 or less, the rubber elasticity becomes strong and the viscosity becomes too high, so that the workability deteriorates. When it is 70 or more, the rubber is in a sol state and it becomes difficult to collect the solidified product.

In carrying out the present invention, octamethyltetracyclosiloxane is used as the dialkylorganosiloxane, tetraethoxysilane is used as the siloxane-based crosslinking agent, and γ- is used as the siloxane-based graft crossing agent.
Use is made of a composite rubber in which a polyalkyl (meth) acrylate rubber component having a main skeleton having a repeating unit of n-butyl acrylate is compounded with a polyorganosiloxane rubber obtained by using methacryloyloxypropyldimethoxymethylsilane. It is preferable.

The composite rubber thus produced by emulsion polymerization can be graft-copolymerized with a vinyl monomer, and is entangled with a polyorganosiloxane rubber component and a polyalkyl (meth) acrylate rubber component. It is correct. The gel content measured by extracting this composite rubber with toluene at 90 ° C. for 12 hours is preferably 30% by weight or less. A more preferable gel content is 10 to 30%.

As the vinyl-based monomer to be graft-polymerized on the composite rubber, aromatic alkenyl compounds such as styrene, α-methylstyrene and vinyltoluene; methacrylic acid esters such as methylmethacrylate and 2-ethylhexylmethacrylate; methylacrylate, Acrylic esters such as ethyl acrylate and butyl acrylate; Vinyl cyanide compounds such as acrylonitrile and methacrylonitrile; Epoxy group-containing vinyl compounds such as glycidyl methacrylate; Various vinyl compounds such as vinyl compounds containing carboxylic acid groups such as methacrylic acid Examples thereof include monomers, which may be used alone or in combination of two or more.

The ratio of the composite rubber to the vinyl monomer in obtaining the composite rubber-based graft copolymer (hereinafter referred to as "graft composite rubber") is based on the weight of the obtained graft copolymer. ~ 95% by weight, preferably 20 ~
It is 90% by weight and 5 to 90% by weight of vinyl monomer, preferably about 10 to 80% by weight. When the vinyl-based monomer is less than 5% by weight, the dispersion of the graft composite rubber component in the resin composition mixed with another resin is not sufficient, and when it exceeds 90% by weight, the impact strength is lowered, which is preferable. Absent.

The graft composite rubber can be obtained by adding a vinyl monomer to the latex of the composite rubber and polymerizing it in a single stage or multiple stages by a radical polymerization technique.

After the graft polymerization is completed, the graft composite rubber can be separated and recovered by introducing the latex into hot water in which a metal salt such as calcium chloride or aluminum sulfate is dissolved, salting out and coagulating. .

The vinyl chloride resin (B) used in the present invention is a vinyl chloride homopolymer and a vinyl chloride copolymer containing 50% by weight or less of a vinyl monomer copolymerizable with vinyl chloride. The polymerization degree of this vinyl chloride resin is usually in the range of 400 to 2500. Other copolymerizable monomers include vinyl acetate, ethylene acrylate, vinyl bromide and the like.

In the resin composition of the present invention, the composition of the graft composite rubber (A) and the vinyl chloride resin (B) is such that the component (A) is 1 to 30% by weight based on the weight of the entire resin composition. The component (B) is preferably constituted so as to be 99 to 70% by weight. If the content of the component (A) is less than 1% by weight, the impact resistance improving effect of the vinyl chloride resin composition is insufficient, and if it exceeds 30% by weight, the mechanical strength of the vinyl chloride resin composition is lowered.

The graft composite rubber and the resin composition of the present invention can be extruded by an ordinary known kneading machine. Examples of such a machine include an extruder, an injection molding machine, a blow molding machine, and an inflation molding machine. Further, the graft composite rubber and the resin composition of the present invention may contain a dye, a pigment, a stabilizer, a reinforcing agent, a filler, a flame retardant, a lubricant, etc., if necessary.

The present invention will be described below with reference to examples. In the Reference Examples and Examples, "parts" and "%" mean "parts by weight" and "% by weight" unless otherwise specified.

In the Reference Example, the particle size of the polyorganosiloxane in the latex was measured by the dynamic light scattering method.
This measurement is a method that utilizes the Brownian motion of particles in latex. When the particles in the latex are irradiated with laser light, they show fluctuations according to the particle diameters, so the particle diameters can be calculated by analyzing these fluctuations. The number average particle diameter and the weight fraction of particles having a particle diameter of 0.1 μm or more were determined using a DLS-700 type manufactured by Otsuka Electronics Co., Ltd.

To measure the swelling degree and gel content of the composite rubber, latex was dropped into isopropanol to coagulate /
The following method was used using the composite rubber obtained by drying.

That is, the degree of swelling was obtained as a value obtained by dividing the weight of toluene occluded by the composite rubber when the composite rubber was immersed in toluene at 23 ° C. for 48 hours by the weight of the composite rubber before immersion. The gel content is 23 ° C in the composite rubber in toluene,
It was determined by extraction treatment for 48 hours.

In the examples, the Izod impact strength was measured by the method of ASTM D258. The load value of the motor during extrusion molding was used as an index of workability.

The glossiness is measured by VGS- manufactured by Nippon Denshoku Kogyo.
Measured according to JIS K 7105 (method for testing optical properties of plastics) at 300A.

The number average particle size of the graft composite rubber and 0.1
The volume fraction of particles of μm or more was determined by observing an ultrathin section sample with a transmission electron microscope. This ultrathin section sample was obtained by melting and mixing 90 parts of PVC and 10 parts of graft composite rubber in an extruder to form a strand, and cutting from this test piece using a microtome.

[0044]

【Example】

Reference Example 1 0.5 part of γ-methacryloyloxypropyldimethoxymethylsilane and 99.5 parts of octamethylcyclotetrasiloxane were mixed to obtain 100 parts of a siloxane-based mixture. 300 parts of distilled water in which 0.67 part of sodium dodecylbenzenesulfonate was dissolved was added to this, and the mixture was stirred with a homomixer at 10,000 rpm for 2 minutes, and then passed through a homogenizer twice at a pressure of 300 kg / cm2 to obtain a stable preliminary. A mixed organosiloxane latex was obtained.

On the other hand, 10 parts by weight of dodecylbenzenesulfonic acid and 90 parts by distilled water were poured into a separable flask equipped with a cooling condenser to prepare a 10% by weight dodecylbenzenesulfonic acid aqueous solution.

With the aqueous solution heated to 85 ° C., the premixed organosiloxane latex was added dropwise over 2 hours, and after the completion of the addition, the temperature was maintained for 3 hours and cooled. The reaction was then neutralized with aqueous sodium hydroxide solution.

Reference Examples 2 to 5 Polyorganosiloxane latex was prepared in the same manner as in Reference Example 1 except that the concentration of the dodecylbenzenesulfonic acid aqueous solution was changed to 15, 5, 3 and 2% by weight, respectively. Obtained.

Reference Example 6 0.5 part of γ-methacryloyloxypropyldimethoxymethylsilane and 99.5 parts of octamethylcyclotetrasiloxane were mixed to obtain 100 parts of a siloxane-based mixture. Distilled water in which 4 parts of dodecylbenzene sulfonic acid and 2 parts of sodium dodecylbenzene sulfonate are dissolved 200
100 parts of this siloxane-based mixture was added to parts, and preliminarily dispersed by a homomixer and emulsified / dispersed by a homogenizer. The premixed organosiloxane latex was heated at 80 ° C. for 5 hours, then cooled, then 2
After standing at 0 ° C. for 48 hours, the pH was neutralized to 7.0 with an aqueous sodium hydroxide solution to complete the polymerization, and a polyorganosiloxane latex was obtained.

Reference Example 7 Production of Grafted Composite Rubber Gf-1: 54.9 parts of the latex obtained in Reference Example 1 was collected, placed in a separable flask equipped with a stirrer, and distilled water 170
After adding the parts, a mixed solution of 59.94 parts of butyl acrylate, 0.06 part of allyl methacrylate and 0.12 part of tert-butyl hydroperoxide was charged and stirred for 30 minutes to impregnate the polyorganosiloxane rubber particles. Nitrogen was replaced by passing a nitrogen stream through the separable flask, and the temperature was raised to 60 ° C. Liquid temperature is 60
When the temperature reached ℃, 0.001 part of ferrous sulfate, 0.003 part of ethylenediaminetetraacetic acid disodium salt, and 0.24 part of Rongalit were dissolved in 10 parts of distilled water, and an aqueous solution was added to initiate radical polymerization. . The liquid temperature rose to 82 ° C. due to the polymerization of the butyl acrylate mixed liquid. This state was maintained for 1 hour to complete the polymerization of butyl acrylate to obtain a composite rubber latex.

The swelling degree of this composite rubber was 64.3% and the gel content was 13.4%.

After the liquid temperature had dropped to 75 ° C., a mixed liquid of 0.12 parts of tert-butyl hydroperoxide and 30 parts of methyl methacrylate was added dropwise to this composite rubber latex over 15 minutes, and then at 70 ° C. at 4 ° C. Hold for a period of time to complete the graft polymerization on the composite rubber.

The obtained latex of the graft composite rubber was gradually dropped into 200 parts of water (25 ° C.) containing 1.5% by weight of calcium chloride to cause coagulation, and then the temperature was raised to 90 ° C. to solidify. Then, the coagulated product is separated from the liquid, and after washing,
After drying at 75 ° C. for 16 hours, 96.8 parts of a dry powder of the graft composite rubber Gf-1 was obtained. The number average particle diameter of this graft composite rubber was 0.05 μm, and the volume fraction of particles larger than 0.1 μm was 5.6%.

Reference Examples 8 to 10 Grafted composite rubber Gf-
Production of 2, Gf-3 and Gf-4: Graft composite rubbers Gf-2, Gf-3 and Gf-4 were obtained by using the latexes obtained in Reference Examples 2 to 4 in the same manner as in Reference Example 7. The results are shown in Table 1.

Reference Examples 11 to 12 Grafted composite rubber Gf
Production of -5 and Gf-6 (for comparative examples): Using the latexes obtained in Reference Examples 5 to 6, graft composite rubbers Gf-5 and Gf-6 were obtained in the same manner as in Reference Example 7. The results are shown in Table 1.

[0055]

[Table 1]

Reference Examples 13 to 14 Grafted composite rubbers Gf-7 and Gf- were prepared in the same manner as in Reference Example 7 except that the amount of allyl methacrylate was changed.
Got 8. The results are shown in Table 1.

Examples 1 to 4 and Comparative Examples 1 and 2 100 parts of polyvinyl chloride resin (hereinafter abbreviated as PVC) having a degree of polymerization of 1000, and graft composite rubbers Gf-1 to Gf-1 obtained in Reference Examples 7 to 12. 7 parts of Gf-6 were mixed. Further, with respect to 100 parts of PVC, 1.5 parts of dibutyltin mercaptide, 1.2 parts of calcium stearate, 0.5 part of glycerin monostearate, 0.2 part of polyethylene wax, 5.0 parts of calcium carbonate, titanium oxide 1. 0
Parts were also mixed, heated to 110 ° C. by a Henschel mixer, and then cooled. Next, using a 30 mmφ extruder, 5 × at 160 ° C
A 12.7 mm square rod was extruded, a V notch (R = 0.25 mm) was attached to the extruded rod, and Izod impact strength was measured. In addition, the glossiness and the extrusion load during molding were measured. The results are shown in Table 2.

[0058]

[Table 2]

Comparative Examples 3 and 4 In Example 1, the graft composite rubbers Gf-7 and Gf- were used.
The results are shown in Table 2 except that 8 was used.

Comparative Examples 5 and 6 In Example 1, the amount of Gf-1 added was 0.5 parts and 40 parts.
The results are shown in Table 2 except that the parts were changed.

[0061]

INDUSTRIAL APPLICABILITY The present invention makes it possible to obtain a molded article which exhibits excellent impact resistance and exhibits good workability.

Front Page Continuation (72) Inventor Koichi Ito 20-1 Miyukicho, Otake City, Hiroshima Prefecture Mitsubishi Rayon Co., Ltd. Central Research Laboratory

Claims (2)

[Claims] 1. A swelling degree for toluene comprising a polyorganosiloxane component (A) and an alkyl (meth) acrylate component composed of an alkyl (meth) acrylate and a polyfunctional alkyl (meth) acrylate is 40 to 70.
The number average particle diameter of the composite rubber is 0.005, which is obtained by graft-polymerizing one or more vinyl monomers.
The composite rubber-based graft copolymer (A) has a particle size of ˜0.08 μm and a volume of particles larger than 0.10 μm is 20% or less of the total particle volume. 2. The composite rubber-based graft copolymer (A) of 1 to 30% by weight and the vinyl chloride resin (B) of 99 to
A resin composition comprising 70% by weight.