JPS63182368A - Matte thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. which gives molded products having excellent impact resistance and matteness, by blending a graft copolymer obtd. from an arom. vinyl monomer, a vinyl cyanide monomer and a diene rubber elastomer with a specified rigid copolymer. CONSTITUTION:5-50pts.wt. arom. vinyl monomer (a) (e.g., styrene) and 3-20pts. vinyl cyanide monomer (b) (e.g., acrylonitrile) are grafted onto 40-75pts.wt. diene rubber elastomer (c) having a gel content of 80-99wt.%, pref. 95-99wt.% and an area-average particle size of 400-1,500Angstrom , pref. 600-1,000Angstrom to obtain a graft copolymer (A). Separately, 40-75pts.wt. alpha-methylstyrene (d) is polymerized with 5-40pts.wt. component (a) excluding the component (d), 5-35pts.wt. component (b) and 0-30pts.wt. copolymerizable vinyl monomer (e) to obtain a rigid copolymer (B). 13-63pts.wt. component A is blended with 87-37pts.wt. component B to obtain the title compsn. contg. 10-25pts.wt. component (c).

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a matte thermoplastic resin composition, and particularly to a molded article having high impact resistance and sufficiently low gloss value, so-called excellent matte property. The present invention relates to a thermoplastic resin composition having excellent rigidity, which can provide a thermoplastic resin composition with sufficiently high heat resistance and surface hardness.

[Prior Art] Thermoplastic resins have been used as molding materials for various products due to their excellent moldability and other properties.

In particular, in recent years, so-called matte thermoplastic resins, which have a high-quality feel and have a low gloss value, have been used as molding materials for automobile interior parts, electrical appliances, camera cases, and the like.

Conventionally, matte thermoplastic resins have been produced by emulsion polymerization, or by using inorganic materials such as titanium,
There are methods of mixing oxides such as magnesium and calcium or their carbonates with thermoplastic resins, or adding diene-based rubbery polymers in the form of latex or powder.

[Problems to be solved by the invention] When attempting to produce an ABS thermoplastic resin with excellent matte properties by emulsion polymerization, it is necessary to reduce the grafting rate of the graft copolymer and reduce the luster by aggregation of the diene rubber elastomers. There are methods to develop erasability, but diene-based rubber elastic materials with medium particle diameters (2000 to 4000A), which are generally used for ABS resins, may suffer from decreased impact resistance or if agglomeration is insufficient. has the disadvantage that a sufficiently satisfactory matte property cannot be obtained. In addition, large particle diameter (5000-700
When performing polymerization using a diene-based comb elastic material (OA) or a diene-based rubber elastic material with a low gel content, the stability of the latex during graft polymerization may decrease, the surface hardness of the molded product may be insufficient, etc. There is a problem.

On the other hand, in the method of mixing an inorganic substance into a resin, physical properties such as impact resistance are significantly deteriorated. On the other hand, with the method of adding a diene-based rubbery polymer, the impact strength decreases little, but
The disadvantage is that the surface hardness and rigidity are greatly reduced. In addition, both methods have the disadvantage that defects such as flow marks and silver streaks are likely to occur in the resulting molded product.

In general, matte thermoplastic resin is used for automobile interior parts, electrical appliance parts, camera cases, etc., which are constantly touched by hands or cloth, so it is particularly important that the surface of the molded product be scratch resistant. However, with conventional technology, matte thermoplastic resins have a sufficiently low gloss value that fully satisfies the required properties, and also have high surface hardness, high single-shot resistance, rigidity, heat resistance, and good moldability. has not been obtained.

[Means and effects for solving the problems] The present invention solves the above conventional problems, and has a sufficiently low gloss value, high surface hardness, high impact resistance, rigidity, heat resistance, and good moldability. A monomer mixture comprising 5 to 50 parts by weight of an aromatic vinyl monomer and 3 to 20 parts by weight of a vinyl cyanide monomer, which provides a matte thermoplastic resin composition. , gel content 80-99% by weight, area average particle diameter 40
Graft copolymer (A) obtained by polymerization in the presence of 40 to 75 parts by weight of a diene-based rubbery elastic material of 0 to 1500A
and 5 to 35 parts by weight of a vinyl cyanide monomer, 40 to 75 parts by weight of α-methylstyrene, 5 to 40 parts by weight of an aromatic vinyl monomer other than α-methylstyrene, and a copolymerizable vinyl monomer. A mixture with a hard copolymer (B) consisting essentially of 0 to 301 L parts of monomer, comprising 13 to 63 parts by weight of the graft copolymer (A) and 87 to 37 parts by weight of the hard copolymer (B). parts by weight, and contains 10 to 25 parts by weight of a diene rubber elastic body.

That is, as a result of intensive studies by the present inventors on methods of increasing matteness, surface hardness, rigidity, etc. without causing a decrease in other properties of thermoplastic resins, the inventors found that the gel content is sufficiently high,
The use of a diene rubber elastomer latex with a small area average particle diameter and its combination with a hard copolymer containing α-methylstyrene etc. are essential conditions for achieving the purpose of the present invention. They discovered this and completed the present invention.

The present invention will be explained in detail below.

- The matte thermoplastic resin composition of the present invention contains 13 to 63 parts by weight of the graft copolymer (A) and the hard copolymer (B).
) 87 to 37 parts by weight, and contains 10 to 25 parts by weight of diene rubber elastic material.

The graft copolymer (A) according to the present invention comprises 5 to 50 parts by weight of an aromatic vinyl monomer and 3 to 50 parts by weight of a vinyl cyanide monomer.
A monomer mixture formed by mixing 20 parts by weight with a gel content of 80 to 99 weight % and an area average particle diameter of 400 to 1500
It is obtained by graft polymerization in the presence of 40 to 75 parts by weight of the diene rubber-like elastic material A.

The diene rubber-like elastic body used in the synthesis of the graft copolymer (A) has an area average particle diameter of 400 to 1500A, preferably 600 to 1000λ, and a gel content of 80 to 99%.
%, preferably 95% or more, but in the present invention, it is an extremely important factor that the area average particle diameter and gel content of the diene rubber-like elastic body are within the above ranges. That is, by using a diene rubber-like elastic material with a small area average particle diameter, the small-particle diene rubber-like elastic material coagulates with each other during kneading with a Banbury mixer, extruder, etc., and the resulting resin becomes matte. Surface hardness and rigidity can be increased by using a diene-based rubber-like elastic body that exhibits high elasticity and impact resistance, and has a high gel content.

If the amount of such diene-based rubber-like elastic material used is less than the lower limit of the range specified in the claims, sufficient effects of improving impact resistance and matteness cannot be obtained. On the other hand, if the amount of diene rubber-like elastic material used exceeds the upper limit of the range specified in the claims, the matting effect will be excellent, but the heat resistance will drop significantly, and the surface hardness and rigidity will be insufficient. I can't get a value.

The graft copolymer (A) preferably contains 50 to 70 parts by weight (in terms of dry weight) of diene-based rubbery elastic latex.
in the presence of 10 to 40 parts by weight of an aromatic vinyl monomer and 5 to 17 parts by weight of a vinyl cyanide monomer! ! It is preferable to synthesize a certain amount by graft polymerization using a polymerization initiator.

The aromatic vinyl monomers used in the synthesis of the graft copolymer (A) include styrene, α-methylstyrene, p-methylstyrene, and vinyl cyanide monomers. Examples include acrylonitrile and methacrylnitrile. In addition, the polymerization initiator may be a thermal decomposition initiator such as potassium persulfate or ammonium persulfate, which is commonly used in ABS graft copolymerization, or a redox initiator such as organic hydroperoxide/iron salt. There is no particular restriction on the method of addition, and any one of batch addition, batch addition, and continuous M addition can be employed.

When an emulsifier is used in the synthesis of the graft copolymer (A), there are no particular restrictions on the emulsifier, but for example, anionic surfactants such as potassium oleate and disproportionated potassium rosinate are used. Further, when using a chain transfer agent, there is no particular restriction on the chain transfer agent, and mercaptans, α-methylstyrene dimer, terpenes, etc. are used.

To synthesize the graft copolymer (A), predetermined amounts of an aromatic vinyl monomer, a vinyl cyanide monomer, and a diene rubber-like elastomer are added to a polymerization initiator, an emulsifier, and a slendering agent. If necessary, an antioxidant is added to the graft polymerization latex which has undergone 0 polymerization. Next, a resin solid is precipitated from the obtained graft polymerization latex. In this case, as the precipitating agent, for example, an aqueous solution of sulfuric acid, acetic acid, calcium chloride, magnesium sulfate, etc. can be used alone or in combination. The graft polymerization latex to which a precipitating agent has been added is heated and stirred, and then the precipitate is separated, and this is washed with water, dehydrated, and dried to obtain a graft copolymer (A).

The aromatic vinyl monomer and the vinyl cyanide monomer constituting the graft copolymer (A) have a good effect on latex stability during graft polymerization, as long as they are within the weight part range specified in the claims. Although it does not have a large effect, if the amount of the aromatic vinyl monomer is less than 5 parts by weight, the stability of the latex may decrease and the resin melt viscosity during molding may increase. Moreover, if the aromatic vinyl monomer exceeds 50 parts by weight, the impact resistance of the resulting resin will decrease. On the other hand, if the amount of the vinyl cyanide monomer is less than 3 parts by weight, the impact resistance and rigidity of the resulting resin will decrease, and if it exceeds 20 parts by weight, the latex stability will decrease and the graft copolymer will tends to cause discoloration.

In any case, the mixing ratio of the aromatic vinyl monomer and the vinyl cyanide monomer is preferably selected within the range of parts by weight as claimed in the claims, and within a range that does not reduce latex stability and resin properties.

On the other hand, the hard copolymer (B) contains 5 to 35 parts by weight of a vinyl cyanide polymer, 40 to 75 parts by weight of α-methylstyrene, and 5 to 35 parts by weight of an aromatic vinyl monomer other than α-methylstyrene.
40 parts by weight and 0 to 30 parts by weight of a copolymerizable vinyl monomer.

In the present invention, the hard copolymer (B) to be mixed with the graft copolymer (A) contains vinyl cyanide monomers, α-methylstyrene, and aromatic vinyl monomers other than α-methylstyrene in the above proportions. It is an extremely important requirement that the copolymer be a hard copolymer with high heat resistance and composed of vinyl monomers and copolymerizable vinyl monomers. It is possible to achieve heat resistance and impact resistance that cannot be obtained by mixing with other materials.

Among the monomers used in the hard copolymer, vinyl aromatic monomers include styrene and p-methylstyrene, and vinyl cyanide monomers include acrylonitrile and methacrylnitrile. etc. Also,
Copolymerizable vinyl monomers include maleimide monomers, such as maleimide, N-methylmaleimide, N-
Examples include ethylmaleimide, N-phenylmaleimide, and acrylic acid ester monomers such as methyl methacrylate and methyl acrylate.

The hard copolymer (B) is synthesized by polymerizing these monomers, but the polymerization method is not particularly limited, and emulsion polymerization, suspension polymerization, etc. are employed.

When the hard copolymer (B) is synthesized by emulsion polymerization, common emulsifiers for emulsion polymerization such as potassium rosinate and sodium alkylbenzenesulfonate can be used as the emulsifier. Further, as the polymerization initiator, an organic or inorganic peroxide type initiator is used, and as a chain transfer agent, mercaptans, α-methylstyrene dimer, terpenes, etc. are used.

When synthesizing the hard copolymer CB) by suspension polymerization, tricalcium phosphite, polyvinyl alcohol, etc. are used as the suspending agent, and sodium alkylbenzene sulfonate, etc. can be used as the suspending aid. . Moreover, organic hydroperoxides can be used as the initiator, and mercaptans, α-methylstyrene, terpenes, etc. can be used as the chain transfer agent.

To synthesize the hard copolymer (B), monomers constituting the same are mixed in predetermined amounts, and a suitable emulsifier or suspending agent, initiator, and chain transfer agent are added and polymerized.

Next, resin solids are precipitated from the hard resin latex obtained by polymerization. In this case, as the precipitating agent, for example, an aqueous solution of sulfuric acid, acetic acid, calcium chloride, magnesium sulfate, etc. can be used alone or in combination. The precipitate is washed with water, dehydrated, and dried as necessary to form a hard copolymer (B
).

The matte thermoplastic resin composition of the present invention comprises the graft copolymer (A) and hard copolymer (B) thus obtained.
), 13 to 63 parts by weight of the graft copolymer (A), preferably 16 to 50 parts by weight, and 87 to 3 parts by weight of the hard copolymer (B).
It is obtained by kneading 7 parts by weight, preferably 84 to 50 parts by weight, using a Banbury mixer, an extruder, a roll mill, etc., and the diene rubber-like elastic material content is 10 to 25 parts by weight. Parts by weight, preferably 12~
It is 20 parts by weight.

When the diene-based rubbery elastic body in the resin composition exceeds 20 parts by weight, although it has excellent matting properties and impact resistance, it tends to cause a decrease in heat deformation resistance, surface hardness, and rigidity. If the diene-based rubbery elastic body is less than 12 parts by weight, heat deformation resistance, surface hardness, and rigidity are excellent, but matting properties are insufficient and impact resistance may be reduced.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Production Examples, Examples, and Comparative Examples, but the present invention is not limited to the following Examples unless it exceeds the gist thereof. In addition, in the following, "1 part" indicates "part by weight".

Production Example 1 Diene-based rubbery elastic body with small particle size and high gel content (US
-1) Production In a stainless steel autoclave equipped with a stirrer, the raw materials of the following composition were charged, and the reaction was started under vacuum at a charging temperature of 60°C,
The temperature was raised to 73°C halfway through. The solid content was measured during the polymerization, and the time when there was no increase in the solid content was considered to be the end of polymerization, and unreacted monomer content was removed by stripping under reduced pressure.

Chichi-nuri Butadiene monomer ioo part Potassium odioleate 4.0 parts t-dodecyl mercaptan 0.2 parts Sodium pyrophosphate 0.3 parts Potassium persulfate 0.3 parts Pure water 150 parts The properties of the obtained rubber latex were as follows.

PH12,4 Gel content: 98% Area average particle diameter 700A The above latex is referred to as rUS-IJ.

Production Example 2 Medium particle size and 80% gel content diene rubber-like elastic body (
Into a stainless steel autoclave equipped with a manufacturing stirrer, the raw materials of the following composition were charged, and the reaction was started under vacuum at a charging temperature of 60°C.
During the process, the temperature was raised to 60 to 78°C. The solid content was measured during the polymerization, and when the polymerization rate reached 85%, the polymerization was terminated and stripping was performed under reduced pressure to remove unreacted monomers.

[Sumi Butadiene monomer 100 parts Disproportionated potassium rosinate 2.5 parts t-dodecyl mercaptan 0.2 parts Sodium pyrophosphate 1.5 parts Potassium persulfate 0.35 parts Pure water 85 parts The properties of the obtained rubber latex were as follows.

PH11.5 Gel content: 80% Area average particle diameter 3200A The above latex is referred to as rUs-2J.

Production Example 3 Production of Graft Copolymers (L-1) to (L-9) Raw materials were charged into a stainless steel polymerization tank equipped with a stirrer according to the formulations shown in Table 1, and polymerization was carried out. The polymerization temperature was started at 60°C, and the temperature was raised to 73°C in the middle.

In addition, diene-based rubber-like elastic latex (US-1, U
S-2) and each monomer were added at once, and the initiator was continuously added over 60 to 100 minutes depending on the amount of monomer.

After polymerization, an antioxidant was added, solid content was precipitated with sulfuric acid, and through the steps of washing, dehydration, and drying, graft copolymer powders L-1 to L-9 were obtained.

Production Example 4 Production of Rigid Copolymers (R-1) to (R-3) Rigid copolymers were produced by emulsion polymerization or suspension polymerization. In the case of emulsion polymerization, polymerization was carried out in a stainless steel polymerization tank equipped with a stirrer, and in the case of suspension polymerization, polymerization was carried out in an autoclave equipped with a stirrer.

The polymerization recipe of the hard copolymer is shown in Table 2.

After the polymerization, precipitation treatment was performed in the same manner as in Production Example 3 to obtain hard copolymer powders R-1 to R-3.

Examples 1 to 6, Comparative Examples 1 to 6 The graft copolymer powders and hard copolymer powders produced in Production Examples 3 and 4 were kneaded in a Banbury mixer and a roll mill with the formulations shown in Table 3 to form a sheet. After pelletizing, molding was performed using a 2-ounce injection molding machine to obtain a molded product.

The obtained molded product was tested for various properties, and the results are shown in Table 3.

Note that the characteristic test was conducted under the following conditions and method.

City 5 value (kg - cm/cm) = ASTM (02
5B) Notched isot, measurement temperature 23℃ Heat distortion temperature (t) -ASTM (D648) 18.6k
g/crr? Load, test piece width 174” Gloss (reflectance) = Suga Test Instruments digital variable angle light meter TL
Using GV-5D, the reflectance is measured at an incident angle of 60° and a reflection angle of 60°.

Surface hardness = ^STM (0785) Rockwell R hardness tensile strength (kg/crr?) -ASTM (0
63B) 178", measurement temperature 23°C. Uneven gloss; determined by visual inspection.

O: No uneven gloss occurs.

Δ: Slight uneven gloss occurs.

×: Uneven gloss occurs.

As is clear from Table 3, the resin composition of the present invention has a good balance of matte properties, impact resistance, heat resistance, surface hardness, and rigidity, and does not cause uneven gloss on the surface of molded products.

On the other hand, in Comparative Examples 1 and 2, although the matte properties were satisfactory, impact resistance, heat resistance, and rigidity were not satisfactory.

In addition, Comparative Examples 3 and 4 used diene rubber elastic bodies with a medium particle size and a gel content of 80%, but satisfactory impact resistance, matteness, rigidity, and uneven gloss were obtained. I can't.

When other rubber-like elastic bodies such as NBR are added as in Comparative Example 5, it is not possible to obtain a material with satisfactory heat resistance, surface hardness, and rigidity.

When mixed with a normal styrene-acrylonitrile copolymer as in Comparative Example 6, the WI! It is not possible to obtain satisfactory properties in terms of hardness, heat resistance, and matte properties.

[Effects of the Invention] As detailed above, according to the matte thermoplastic resin composition of the present invention, it is possible to provide a molded article that has impact resistance and has a sufficiently low gloss value and excellent so-called matte properties. I can do it,
Moreover, the heat resistance and surface hardness are sufficiently high, and a thermoplastic resin molded article with excellent rigidity can be obtained. Therefore, such a thermoplastic resin composition of the present invention is extremely useful as a molding material for automobile interior parts, electrical appliances, camera cases, and the like.

Claims (2)

[Claims] (1) A monomer mixture consisting of 5 to 50 parts by weight of an aromatic vinyl monomer and 3 to 20 parts by weight of a vinyl cyanide monomer is mixed with a gel content of 80 to 99% by weight and an area of Diene-based rubbery elastic body 40-7 with an average particle diameter of 400-1500 Å
Graft copolymer (A) obtained by polymerization in the presence of 5 parts by weight, 5 to 35 parts by weight of vinyl cyanide monomer, α
- A hard copolymer consisting essentially of 40 to 75 parts by weight of methylstyrene, 5 to 40 parts by weight of an aromatic vinyl monomer excluding α-methylstyrene, and 0 to 30 parts by weight of a copolymerizable vinyl monomer. A mixture with the polymer (B), comprising 13 to 63 parts by weight of the graft copolymer (A) and 87 to 37 parts by weight of the hard copolymer (B), and 10 to 25 parts by weight of the diene rubber elastic body. A matte thermoplastic resin composition comprising: (2) The diene rubber-like elastic body constituting the graft copolymer (A) has a gel content of 95 to 99% by weight and an area average particle diameter of 600 to 1000 Å. The resin composition described in .