JPS63146956A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To obtain a thermoplastic resin composition having excellent chemical resistance and impact resistance, by mixing a rubber-modified thermoplastic resin component containing a hydroxyl-containing vinyl monomer as a copolymerized component with a polyamide resin component at a specific ratio. CONSTITUTION:The objective thermoplastic resin composition is produced by mixing (A) 60-98wt% rubber-modified thermoplastic styrene resin component consisting of a rubber-modified styrene polymer (preferably ABS resin) or its blend with a styrene polymer and containing an OH-containing vinyl monomer (preferably 2-hydroxyethyl methacrylate) as a copolymerized component in at least one of the above polymers with (B) 2-40wt% polyamide resin component (preferably nylon 6) preferably using a vent-type extruder at 210-300 deg.C. The composition contains the above hydroxyl-containing vinyl monomer as a copolymerized component in an amount of 0.5-15wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a thermoplastic resin composition with excellent chemical resistance.

b. Conventional technology Conventionally, styrenic thermoplastic resins modified with rubber-like polymers have been used in a wide range of applications because of their excellent moldability, molded product appearance, mechanical strength, and improved impact resistance. used.

However, these rubber-modified styrenic thermoplastic resins are inferior to other crystalline resins such as polyethylene, polypropylene, and polyamide, fluororesins, and thermosetting resins in terms of chemical resistance, so improvements in this respect are desired. It was rare. In particular, cracks caused by the interaction of solvent and stress, i.e., solvent stress cracking,
) has become an important problem in industrial use.

This type of solvent cranking is caused by the effect of the pika agent contained in the vinyl chloride resin on the rubber-modified styrene resin in parts where vinyl chloride resin and rubber-modified styrene resin are in contact with each other. Phenomenon such as cracks may occur in modified styrene resin.
It has been desired to develop a rubber-modified styrenic resin with good plasticity resistance that does not cause this phenomenon.

Therefore, in order to improve the chemical resistance of rubber-modified styrenic resins, there has been a conventional method (i) of introducing a large amount of a compound having a polar group such as acrylonitrile into the styrene substrate (for example, Japanese Patent Laid-Open No. 59-53513 etc.) or (i
i) A method of mixing crystalline resins such as polypropylene and polyamide (for example, JP-A-57-53549,
Methods such as Japanese Patent Publication No. 38-23476) are known.

Problems to be Solved by the C0 Invention However, the conventional method (i) does not improve chemical resistance sufficiently, and also, because a large amount of polar groups are introduced into the resin, fluidity It has the disadvantage that the moldability is poor due to a decrease in the processability.

In addition, in the case of the conventional method (ii), although a significant improvement in chemical resistance is seen, the compatibility with the rubber-modified styrene resin deteriorates, resulting in a decrease in impact resistance. It had the disadvantage that delamination and delamination were observed.

On the other hand, as a method for improving the compatibility, a method is to copolymerize a specific monomer with a rubber-modified styrenic resin, for example, when producing a rubber-modified styrenic resin, an ethylenically unsaturated carbonamide is copolymerized and then the polyamide is copolymerized. How to mix (
JP-A No. 58-93745) is known, but according to additional experiments conducted by the present inventors, the effect of improving compatibility cannot be said to be sufficient, and furthermore, the resulting resin is colored. It had the following drawback.

d. Means for Solving the Problems In order to solve these conventional problems, the present inventors have proposed mixing a crystalline resin and further improving its compatibility with the rubber-modified styrenic resin. As a result of intensive studies with the main purpose of When mixed with polyamide resin component in a specific ratio,
The present invention has been achieved by discovering that a thermoplastic resin composition can be obtained which has excellent chemical resistance and good general physical properties such as impact resistance, and which has improved the above-mentioned conventional problems.

That is, the present invention provides a rubber which is composed of a rubber-modified styrenic polymer or a rubber-modified styrenic polymer and a styrene-based polymer, and in which at least one of the polymers contains a hydroxyl group-containing vinyl monomer as a copolymerization component. 0.5 to 15% by weight of the hydroxyl group-containing vinyl monomer as a copolymerization component in a composition consisting of 60 to 98% by weight of a modified styrenic thermoplastic resin component and 2 to 40% by weight of a polyamide heavy phase resin component. % of the thermoplastic resin composition.

e0 Detailed Description of the Invention (A) Rubber-modified styrenic thermoplastic resin component The rubber-modified styrenic thermoplastic resin component used in the present invention is: ■Rubber-modified styrenic polymer or ■Rubber-modified styrenic polymer. It is a mixture of a polymer and a styrene polymer (not rubber-modified), and a rubbery polymer is mixed into a specific styrene polymer for the purpose of obtaining a high degree of impact resistance. A simple mechanical blending method may be used as the mixing method, but in order to obtain good compatibility, so-called graft copolymerization, in which styrene monomers etc. are graft copolymerized in the presence of a rubbery polymer, is recommended. Those obtained by prescription are more preferred. Also,
It is also preferable to use a polymer obtained by a so-called graft-blend method, in which a rubber-modified styrenic polymer (graft polymer) obtained by this method is mixed with a styrenic polymer obtained by a separate method.

Rubber polymer Examples of the rubber polymers used include polybutadiene, styrene-butadiene copolymers, acrylic copolymers, ethylene/propylene copolymers, chlorinated polyethylene, and polyurethane. ,
Among them, it is preferable to use polybutadiene.

Rubber/Styrenic Thermoplastic Resin The rubber-modified styrenic thermoplastic resin component used in the present invention can be selected from: (1) a rubber-modified styrenic polymer or (2) a mixture of a rubber-modified styrenic polymer and a styrene-based polymer. It is what it is. In the case of (2), the polymer contains a hydroxyl group-containing vinyl monomer as a copolymerization component, and in the case of the mixture (2), at least one of the polymers contains a styrene monomer and the copolymer. It is copolymerized with a styrene monomer and contains a hydroxyl group-containing vinyl monomer as a copolymerization component.

Examples of the styrene monomer include styrene, α-methylstyrene, and bromostyrene, among which styrene is most suitable.

Examples of the hydroxyl group-containing vinyl monomer include hydroxystyrene, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, and 2-hydroxyethyl acrylate.
Examples include 2-hydroxypropyl, 2-hydroxypropyl methacrylate, and among these, it is preferable to use 2-hydroxyethyl methacrylate.

It is important to use the hydroxyl group-containing vinyl monomer in an amount of 0.5 to 15% by weight, preferably 1 to 10% by weight, in the entire composition containing the polyamide resin component described below. If the amount used is less than 0.5% by weight, the compatibility with the polyamide resin component will decrease, resulting in a decrease in impact resistance, which is not preferable. Moreover, if the amount exceeds 15% by weight, impact resistance and fluidity will be lowered, and the surface gloss of the molded article will be lowered, which is not preferable.

Furthermore, if necessary, it is possible to carry out copolymerization using a comonomer other than the hydroxyl group-containing vinyl monomer that is copolymerizable with these styrene monomers. Such comonomers include acrylonitrile, methacrylonitrile, methyl methacrylate, N-phenylmaleimide, N-cyclohexylmaleimide, and the like.

Generally, it is difficult to develop impact resistance when using a styrene monomer alone, so it is preferable to copolymerize acrylonitrile.

When copolymerizing a hydroxyl group-containing vinyl monomer with a rubber-modified styrene thermoplastic resin, the base material to be present and graft copolymerized includes: 1) a rubbery polymer, 2) a graft layer of a graft polymer, or 3. ) non-grafted styrenic polymers, among which 2) or 3
), especially 3) is preferred.

Specifically, the rubber-modified styrenic thermoplastic resins obtained in this manner include conventional acrylonitrile-butadiene-styrene resin (ABS resin), acrylonitrile-ethylenepropylene-styrene resin (ABS resin),
Methyl methacrylate-butadiene-styrene resin (AB
S resin), acrylonitrile-butanene-methyl methacrylate-styrene resin, acrylonitrile-n-butyl acrylate-styrene resin (AAS resin), rubber modified polystyrene (high impact polystyrene: HIP
S) When producing a copolymer resin such as a heat-resistant rubber-modified styrenic resin using α-methylstyrene, styrene is added in the copolymer resin or in the styrenic polymer mixed with the copolymer resin. A hydroxyl group-containing vinyl monomer is contained in the copolymer, which is obtained by polymerizing a part of the monomers with a hydroxyl group-containing vinyl monomer. Among these rubber-modified styrene-based thermoplastic resins, those obtained by copolymerizing and containing a hydroxyl group-containing vinyl monomer in the conventional ABS resin are most suitable.

The above rubber-modified styrenic thermoplastic resin is produced by emulsion polymerization, solution polymerization, bulk polymerization, suspension polymerization, or the like.

In addition, a polymerization initiator used in the polymerization, a molecular weight regulator,
As emulsifiers, dispersants, solvents, etc., those normally used in these polymerization methods can be used as they are. A preferred method of the above production method is to use monomers and additional emulsifiers, monomers, and polymerization initiators in the presence of a rubbery polymer obtained by emulsion polymerization, generally at a polymerization temperature of 30°C.
~150'c, polymerization time 1-15 hours, polymerization pressure car 1
．． Graft copolymer obtained by graft copolymerization under conditions of 0 to 5.0 kg/a (including ungrafted styrenic polymer) and styrenic polymer obtained by emulsion polymerization or solution polymerization. This is a manufacturing method by mixing.

(B) Polyamide resin component The polyamide resin component used in the present invention is an injection moldable polyamide resin commonly known as nylon resin, such as polylactam such as polycaprolactam (nylon 6) or polyhexane. Polyamides obtained from aliphatic diamines and aliphatic dicarboxylic acids such as methyleneaziboamide (nylon 6.6), polyhexamethyleneadipamide (nylon 6.10), and polytetramethyleneadipamide (nylon 4.6). There is resin.

Among these polyamide resins, it is preferable to use nylon 6 or nylon 6.6.

(C) Production of thermoplastic resin composition A thermoplastic resin composition is produced by mixing a rubber-modified styrenic thermoplastic resin component and a polyamide resin component.The specific method is as follows. be.

The rubber-modified styrenic thermoplastic resin contains 60% of the rubber-modified styrenic thermoplastic resin in the composition.
It is blended to contain up to 98% by weight, preferably 70 to 5% by weight. If it is less than 60% by weight, the heat deformation temperature and impact resistance of the resulting resin will decrease, which is not preferable.

Further, if the content exceeds 98% by weight, chemical resistance will decrease, which is not preferable.

Next, the polyamide resin component is added to the composition in a range of 2 to 4 times.
It is important to contain 0% by weight, preferably 5 to 30% by weight. If the polyamide resin component contained in the composition is less than 2% by weight, the chemical resistance of the resulting thermoplastic resin composition will decrease, which is not preferable. Also,
It is not preferable that the polyamide resin component has a tensile strength exceeding 40 because the heat deformation temperature and impact resistance decrease.

The above-mentioned rubber-modified styrene thermoplastic resin component and polyamide resin component can be mixed using various methods commonly used for mixing thermoplastic resins, such as a Banbury mixer, a Brabender, a plastomill, a kneader, and a vented extruder. Among these methods, a method using a vented extruder is preferred.

In addition, the form of each component resin before mixing can be pellets, beads, powder, flakes, etc., but the mixing temperature needs to be higher than the melting point of the polyamide to be mixed, and generally about Preferably, the temperature is between 210 and 330°C. Further, since rubber-modified thermoplastic resins are generally thermally unstable at temperatures exceeding 300°C, the optimum temperature is 210 to 300°C.

In addition, when producing a rubber-modified styrenic thermoplastic resin by a graft-blend method, a graft polymer,
It is possible to simultaneously mix the styrenic polymer and polyamide resin.

In the thermoplastic resin blended in this way, the hydroxyl group-containing vinyl monomer is introduced into the rubber-modified styrenic thermoplastic resin, so the hydroxyl group makes some contribution to the effect of improving compatibility. It is thought that this is the case.

Generally, it is a conventional chemical theory that compounds with similar structures are soluble. The method of copolymerizing saturated carbonamide to improve compatibility with polyamide resin is the same as the idea of introducing carbonamide, which has a similar structure to polyamide resin, into the molecule, and is the same as the general concept described above. It can be expected that the effect will also be excellent.

However, this method of improving compatibility by introducing a hydroxyl group into a molecule cannot be said to be effective because the hydroxyl group, the vinyl monomer contained therein, and the polyamide resin cannot be said to be compounds with very similar structures. The development of the effect was completely unexpected.

Although the details of the effects of the present invention are unknown, it is likely that intermolecular forces such as hydrogen bonds act between hydroxyl groups and amide bonds, which contributes to compatibility, or that the polyamide resin It is thought that this may be due to the reaction between the terminal amino group or carboxyl group and the hydroxyl group, which contributes to compatibility, but this is currently unknown.

(D) Other compounding agents In addition to the above-mentioned essential components, the thermoplastic resin composition of the present invention may optionally contain a lubricant, an antistatic material, an antioxidant, a flame retardant, an ultraviolet absorber, a photooxidant, It is possible to mix compounding agents and additives commonly used in thermoplastic resin compositions of this type, such as colorants and inorganic fillers such as glass fibers.

f. Example Next, the present invention will be explained in more detail with reference to Examples.

Parts by weight in this example are simply abbreviated as "parts."

Production Example 1 (Graft copolymers G-1, G-2) A chemical solution with the batch preparation composition shown in Table 1 was added to a 71 glass flask equipped with a stirring blade, and the air inside the flask was replaced with nitrogen. After that, the temperature inside the flask was raised to 40°C while controlling the jacket at 70°C. And water 10
0.3 part of sodium pyrophosphate, 0.35 part of dextrose, 0.01 part of ferrous sulfate, and 0.1 part of cumene hydroperoxide were added to start the polymerization reaction.

One hour after starting the reaction, the chemical solution of the incremental mixture shown in Table 1 was continuously added for 3 hours, and then the reaction was continued for another 1 hour.

2.6-sheet tert-butyl para-cresol 1.0 as an anti-aging agent was added to the obtained graft copolymer latex.
sulfuric acid (2 parts per 100 parts of polymer)
was added and solidified at 90°C. And separate this,
Washed with water, dehydrated, and dried to obtain graft copolymers G-1 and G-2
I got it.

Table-1 Production Example 1 (Graft copolymers G1, G2)■)
Made by Japan Synthetic Rubber ■ 1) Using 0700 polybutadiene latex 2) #0561
Production example 2 using styrene-butadiene copolymer Latte Nox
(Styrenic polymers To1 to Toro) The chemical solution shown in Table 2 was added to a 71 glass flask equipped with a stirring blade, and after replacing the air inside with nitrogen, the inside was heated while controlling the jacket at 70°C. The temperature was raised to 50°C. And water 4
0.3 part of potassium persulfate dissolved in 1 part of water and 0.1 part of sodium sulfite dissolved in 1 part of water were added, and a copolymerization reaction was carried out for 3 hours.

Calcium chloride (2 parts per 100 parts of polymer) was added to the obtained styrenic polymer latex and coagulated at 90°C. Then, this was separated, washed with water, dehydrated, and dried to obtain styrenic polymers 1) to Toro shown in Table 2.

Production Example 3 (Graft Polymer G-3) After purging the inside of a stainless steel reactor equipped with a paddle-type stirring blade with nitrogen, the iodine value was 15, the Mooney viscosity was 65, the propylene content was 43% by weight, and ethylidene norbornene was used as the diene component. 24 parts of EPDM (JSREP-24 manufactured by Japan Synthetic Rubber Co., Ltd.), 56 parts of styrene, 20 parts of acrylonitrile, and 100 parts of toluene were charged and stirred at 50°C until the rubber was completely dissolved. .1 part, dibenzoyl peroxide 0.2
part, t-butylperoxy-1-propyl carbonate)
After adding 0.2 part of dicumyl peroxide and 0.1 part of dicumyl peroxide, the temperature was raised to 80°C for 3 hours, then the temperature was raised to 100'C for 3 hours, and the temperature was further raised to 125°C for 3 hours. The polymerization reaction was carried out for a total of 9 hours.

After removing unreacted monomers and solvent by steam distillation,
A polymer was obtained by crushing and drying.

S Examples 1 to 9, Comparative Examples 1 to 7 Graft copolymers G-1 and G-2 obtained in Production Example-1
, Styrenic polymers obtained in Production Example 2 - Toro, Styrene-acrylonitrile polymer resin MS-240 manufactured by Japan Synthetic Rubber ■ (24.5% by weight of bound acrylonitrile)
, methylethyltokene at 30°C [η) -0,60)
, and east side type nylon 6, Amiran CM-1'0
No. 17 was mixed using a Henschel mixer at the blending ratio shown in Table 3.

Incidentally, during the mixing, 0.0% of ethylene bisstearylamide was added.
63 parts, distearyl pentaerythritol diphosphite 0.08 parts and magnesium stearate) 0
．． 13 parts were added as an additive component.

Furthermore, the mixture was granulated at a temperature of 230°C using a 30m/m twin-screw vented extruder, dried at 90°C, and then injection molded at 230°C to obtain various physical properties shown in Table 3. It was measured.

The physical properties were measured using the following method.

Izot impact strength: AST) I I) 256 (notched) Melt flow index: ASTM 01
238 (240°C) gloss: ASTM D523 (3
tm thickness) Constant strain solvent crack: Test piece (178"
x 175" x 5") with a constant strain of 0.5%, apply brake oil (BO) to the bent part, and
The time until breakage occurred when the sample was left at ℃ was measured. Also, under the condition of strain rate 1.0%, dioctyl phthalate (
A similar measurement was performed using DOP (abbreviated as DOP). The longer the time, the better the chemical resistance. In the case of BO, 5 hours or more (
In the case of DOP, the target value was 101 (r or more (several hours with normal ABS)).

As shown in Examples 1 to 9, the thermoplastic resin composition of the present invention has excellent impact resistance as shown by Izod impact strength, fluidity property as shown in melt flow index, heat resistance as shown in heat distortion temperature, and glossiness. It satisfies the physical properties normally required of rubber-modified styrenic thermoplastic resins, such as the surface appearance of molded products shown in , and has extremely good chemical resistance, as exemplified by constant strain solvent cracks. Ta.

Furthermore, Examples 7 to 9 had particularly excellent impact resistance, and significantly improved the Izot impact strength of the general ABS resin (Comparative Example 1).

Comparative Example 1 shows the physical properties of a general ABS resin which is outside the range of the thermoplastic resin composition of the present invention, but the chemical resistance is not sufficient.

Furthermore, Comparative Example 2 shows a simple blend of a normal ABS resin component and a polyamide resin component without copolymerizing a hydroxyl group-containing vinyl monomer, and although the chemical resistance is good, the impact resistance is significantly reduced.

Furthermore, Comparative Example 3.4 describes an example outside the range regarding the mixing ratio of the rubber-modified styrenic thermoplastic resin component copolymerized with the hydroxyl group-containing vinyl monomer of the present invention and the polyamide resin component. When the polyamide resin component is less than 2% by weight and the rubber-modified styrene thermoplastic resin component is more than 98% by weight, this indicates that the chemical resistance is insufficient (Comparative Example 3). In addition, the polyamide resin component is 40% by weight.
and the rubber-modified styrenic thermoplastic resin component exceeds 60%.
If it is less than 1%, the chemical resistance is good, but the heat distortion temperature and impact resistance are lowered, which is not preferable (Comparative Example 4).

Furthermore, Comparative Example 5.6 describes an example outside the range regarding the content of the hydroxyl group-containing vinyl monomer in the rubber-modified styrenic thermoplastic resin component. It is shown that if the amount is less than 0.5% by weight, the impact resistance decreases, which is not preferable (Comparative Example 5). Further, it is shown that if the content exceeds 15% by weight, impact resistance and fluidity are lowered, and glossiness is lowered, which is not preferable (Comparative Example 6).

Comparative Example 7 is an example in which acrylamide was copolymerized without using a hydroxyl group-containing vinyl monomer, but it had the disadvantage that impact resistance was insufficient and the molded product was colored yellow. It shows.

Example 10.1) An experiment similar to Example 1.2 was conducted using nylon 6.6 (Amiran CM3001 N manufactured by Toshi) as the polyamide. However, the temperature of extrusion and injection molding was 275°C. The results obtained are shown in Table-4. A thermoplastic resin with good chemical resistance and general physical properties was obtained.

Table 4 Evaluation of sliding properties and paintability As practical physical properties other than chemical resistance, sliding properties and paintability were evaluated for the molded products obtained in Example 1.2 and Comparative Example 1. The results are shown in Table-5.

The measurement method was as shown below.

The thermoplastic resin composition of the present invention has better sliding properties and paintability than ordinary rubber-modified styrenic thermoplastic resins.

Three cylindrical samples (5tmφX30mm) were placed on a rotating disk.
After this installation, the torque generated when the metal disc is pressed with constant pressure and rotated at a constant speed is measured, and the coefficient of dynamic friction is calculated using the following formula. f=F/P (F: friction force, P: normal force, f: dynamic friction coefficient) The lower the dynamic friction coefficient, the better the sliding characteristics.

Paintability ■ The external molded product (plate shape) was coated with urethane paint Hi-Urethane #5000 manufactured by Nihon Yushi Kogyo ■ to a film thickness of 2 μm. After drying at 70° C. for 20 minutes, the appearance and appearance of cracks, crazes, and suction on the surface of the coating film were visually evaluated according to the following evaluation criteria.

◎: Very good, 0: Good, △: Slightly poor, ×: Bad ■ Adhesion The above-mentioned urethane paint was re-coated to a thickness of 40 μm to the undercoated product whose appearance was observed above.

Adhesion was evaluated by observing the state of the paint film after repainting and according to the following evaluation criteria.

◎: Very good, ○: Good, △: Slightly swollen paint film, ×: Large swell of paint film Table 5 Evaluation of sliding properties and paintability Example 12.13 and Comparative Example 8.9 Using graft polymer G-3 obtained in Production Example 3 and styrenic polymer G-4 obtained in Production Example 2, Examples 1 to 6,
Experiments similar to Comparative Examples 1 to 7 were conducted. As shown in Table 6, the effects of the present invention were obtained even when AES resin was used, and - grain properties were good and chemical resistance was good.

Table 6 [-] Effects of the Invention The thermoplastic resin composition of the present invention has excellent chemical resistance and impact resistance as described in the examples above. It is a thermoplastic resin composition that is excellent and also has good other general physical properties such as moldability.

Furthermore, it is an extremely useful resin composition industrially because it has excellent sliding properties and paintability, and is also excellent in solvent stress cranking.

Patent applicant: Japan Synthetic Rubber Co., Ltd. Agent: Hisao Okuyama (and 2 others)

Claims (6)

[Claims] (1) (A) Rubber consisting of a rubber-modified styrenic polymer or a rubber-modified styrenic polymer and a styrene-based polymer, and at least one of the polymers contains a hydroxyl group-containing vinyl monomer as a copolymerization component. Modified styrene thermoplastic resin component 60-98% by weight and (B) polyamide resin component 2-2%
1. A thermoplastic resin composition comprising 0.5 to 15% by weight of the hydroxyl group-containing vinyl monomer as a copolymerization component in a composition comprising 40% by weight. (2) The thermoplastic resin composition according to claim (1), wherein the hydroxyl group-containing vinyl monomer is 2-hydroxyethyl methacrylate. (3) The thermoplastic resin composition according to claim (1), wherein the rubber-modified styrenic thermoplastic resin is an ABS resin. (4) The thermoplastic resin composition according to claim (1), wherein the polyamide resin is nylon 6. (5) Claim (1) wherein the hydroxyl group-containing vinyl monomer is 2-hydroxyethyl methacrylate, the rubber-modified styrene thermoplastic resin component is ABS resin, and the polyamide resin component is nylon 6. The thermoplastic resin composition described in . (6) The rubber-modified styrenic thermoplastic resin component containing a hydroxyl group-containing vinyl monomer as a copolymerization component is composed of a styrenic polymer obtained by copolymerizing a rubber-modified styrenic polymer and a hydroxyl group-containing vinyl monomer. The thermoplastic heavy composition according to claim (1), which is a rubber-modified styrenic thermoplastic resin.