JPH0514737B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention is particularly excellent in heat cycle resistance of plating film strength. This invention relates to an ABS resin composition. <Conventional technology> Conventionally, ABS resin has been the mainstream resin used for plating, and its plating film is beautiful, the plating film has high peel strength, and it also has excellent heat cycle resistance. Since then, we have established a solid position in the application of plastic plating. However, recently, demands for improved heat cycle resistance have become more severe, especially in automotive applications, and the reality is that existing plating grades cannot meet these demands. For example, specifically, it is required that the appearance of a plated product does not change even if it is subjected to heat cycles of -40°C to 85°C 3 to 10 times. To increase the adhesion strength of the plating film
Publication No. 6222 proposes a method of adding a styrene-butadiene block copolymer to ABS resin, but although this method increases the adhesion strength of the plating film, the smoothness of the molded product surface may be lost. , there were many problems such as the molded product being easily damaged, and it was not practical. On the other hand, the method of adding special functions to ABS resin by adding organosilicon compounds is particularly useful in the field of improving impact resistance, as seen in Japanese Patent Publications No. 1118-1982 and No. 29947-1973. It has been adopted. Furthermore, heat-resistant ABS compositions that can be plated by adding organosilicon compounds to heat-resistant ABS or heat-resistant ABS alloys have been proposed in JP-A-56-81355 and other publications. <Problems to be Solved by the Invention> This heat-resistant ABS containing organosilicon compounds exhibits extremely excellent heat-resistant cycling properties, but since the matrix resin layer of the heat-resistant resin is difficult to be etched,
This method has problems such as a narrow range of etching conditions and the addition of organosilicon compounds, which leads to a decrease in the rigidity of the molded product. <Means for Solving the Problems> In view of this situation, the present inventors have found that the plating film has excellent heat cycle resistance and peeling strength, and that the plating condition width that allows plating is lower than that for conventional plating.
As a result of intensive research with the aim of providing a composition that has favorable characteristics as a plating composition, such as being wider than ABS and having fewer bleeds during molding, we found that ABS alloy contains styrene-butadiene copolymer and organosilicon. We have discovered that by using these compounds together, we can obtain an excellent ABS composition for plating that has no practical problems in both heat-resistant and general applications by adding a very small amount of organosilicon compound, and have developed the present invention. It has been reached. That is, the present invention provides: (a) a graft copolymer (A) 5 to 75 parts by weight of polybutadiene latex in which an aromatic monovinyl monomer and a vinyl cyanide monomer are partially graft-polymerized in advance; 95 parts by weight and (b) styrene containing 5 to 45 parts by weight of styrene.
95 to 75 parts by weight of a graft copolymer (B) obtained by partially graft-polymerizing an aromatic monovinyl monomer and a vinyl cyanide monomer to 15 to 75 parts by weight of a butadiene copolymer latex; and (c) aromatic. A mixture of 0 to 85 parts by weight of a copolymer (C) obtained by copolymerizing 50 to 85 parts by weight of a group monovinyl monomer and 50 to 15 parts by weight of a vinyl cyanide monomer ((A)
+ (B) + (C) total 100 parts by weight) (d) The viscosity at 25°C is 10 to 100,000 centistokes, and the viscosity at 25°C of a 0.5% by weight solution in toluene is 25°C.
The surface tension at is 26.5 dyn/cm or less,
Compounding 0.01 to 0.5 parts by weight of an organosilicon compound having a repeating unit represented by the following formula (),
A resin composition for plating with excellent plating properties. (Here, R ₁ and R ₂ represent one or more groups selected from a hydrogen atom, an alkyl group, an aralkyl group, a carboxymethyl group, a polyether alkyl group, an epoxyalkyl group, a trifluoromethyl group, and a phenyl group, and n indicates an integer greater than or equal to 1). The present invention will be specifically explained below. The resin used in the present invention can be obtained as follows. The aromatic monovinyl monomers used in the present invention include aromatic monovinyl monomers such as styrene, α-methylstyrene, vinyltoluene, o-ethylstyrene, o,p-chlorostyrene, and vinyl cyanide monomers. As the monomer, acrylonitrile, methacrylonitrile, ethacrylonitrile, etc. are used. Regarding the composition ratio of the monomers in graft polymerization, aromatic monovinyl monomers and vinyl cyanide monomers are mixed in an arbitrary ratio. The vinyl cyanide monomer content is selected from the range of 60 to 80% by weight and 40 to 20% by weight of the vinyl cyanide monomer. The graft copolymer (A) used in the present invention is prepared by first charging 15 to 75 parts by weight, preferably 30 to 70 parts by weight, of polybutadiene latex into a polymerization tank, and then continuously removing unreacted monomers. Obtained by supplying. The polymerization initiator may be either oil-soluble or water-soluble, or they may be used in combination. The graft copolymer (B) used in the present invention is
It can be produced in the same manner as graft copolymer (A). Further, although the polybutadiene latex and the styrene-butadiene copolymer latex may be individually graft-polymerized, it is also possible to blend them in advance and then subject them to graft polymerization. According to this method, the graft polymer (A),
(B) can be manufactured at the same time. Any method can be used to obtain the resin from the polymer latex, such as coagulating the polymer latex with mineral acid, electrolyte, etc., and recovering the polymer by filtering, washing, dehydration, and drying. In the resin powder thus obtained, the proportion of rubbery polymer in the final resin component is preferably 5 to 30% by weight.
Styrene-acrylonitrile copolymer, α-
Graft polymers (A), (B), and copolymers (C) are prepared by blending methylstyrene/styrene/acrylonitrile copolymers and kneading them using a Banbury mixer, rolls, extruder, etc. A mixture is obtained. The graft copolymer (A) and the graft copolymer (B) can be blended in any weight ratio within the range of 5/95 to 95/5, but for example, the styrene of the graft copolymer (B) - If the styrene content of the butadiene copolymer latex is 25%,
40/60 to 90/10 is preferred. Graft copolymer (A)
If the content of the graft copolymer (B) is too low, it is difficult to develop impact resistance. On the other hand, if the content of the graft copolymer (B) is too low, the effect of improving heat cycle resistance becomes small. The organosilicon compound used in the present invention has a viscosity at 25°C of 10 to 100,000 centistokes, a surface tension of 0.5% by weight solution in toluene at 25°C of 26.5 dyn/cm or less, and is expressed by the following formula (). with the repeating units shown. Here, R ₁ and R ₂ represent one or more groups selected from a hydrogen atom, an alkyl group, a carboxymethyl group, an aralkyl group, a polyether alkyl group, an epoxyalkyl group, a trifluoromethyl group, and a phenyl group, and n is Indicates an integer greater than or equal to 1. Preferred specific examples of R ₁ and R ₂ include a hydrogen atom, a methyl group, an ethyl group, a propyl group,
Lower alkyl groups such as butyl groups; aralkyl groups such as phenylmethyl, phenylethyl, tolylmethyl, and xylylmethyl groups; polyether alkyl groups such as polyethylene oxide methyl groups, polyethylene oxide methyl groups, and polyethylene oxide ethyl groups; glycidyl groups, Epoxymethyl groups such as 3-epoxypropylmethyl groups,
Examples include trifluoromethyl group, carboxymethyl group, and phenyl group. Particularly preferred are a hydrogen atom, a methyl group, a phenyl group, a polyethylene oxide methyl group, a glycidyl group, and a carboxymethyl group. The viscosity range of such organosilicon compounds is 25°C.
10 to 100,000 centistokes, preferably 100 to 50,000 centistokes.
Low viscosity products have many volatile components, which can cause mold stains or cause paint to repel during painting. On the other hand, materials over 100,000 CS are difficult to handle and require a large amount of energy to disperse, making them impractical. Furthermore, the surface tension of the organosilicon compound used in the present invention in a 0.5% by weight solution in toluene is
It must be 26.5 dyn/cm or less. If the surface tension exceeds 26.5 dyn/cm, the effect of improving the heat cycle resistance of the plating film will be significantly reduced, which is not preferable. The amount of the organosilicon compound to be added is 0.01 to 0.5 part, preferably 0.03 parts, based on 100 parts by weight of the total amount of graft copolymers (A), (B) and copolymer (C).
~0.3 parts. If it is less than 0.01 part, the effect of improving heat cycle resistance will be small, and if it is more than 0.5 part, it will bleed onto the surface of the molded product, causing mold stains, or weakening the adhesion strength of the plating film, which is not preferable. In addition to the organosilicon compound, the resin composition of the present invention may contain commonly used stabilizers, plasticizers, pigments, etc., if necessary. The finally obtained resin composition can be molded by injection molding, extrusion molding, or other molding methods, and then plated in a conventional manner using ordinary ABS plating equipment. <Example> Hereinafter, the method of the present invention will be explained in detail with reference to Examples. In addition, the heat cycle resistance used in the examples,
Peeling strength, impact strength, and viscosity were measured according to the following methods. Heat cycle resistance: After leaving the plated product (175 mm x 35 mm x 90 cm, 2 mm thick, 4-point gate box) at room temperature for 24 hours,
Place in the oven at 85℃ and leave for 1 hour. Take out,
Leave at room temperature for 15 minutes, then immediately place in -40°C freezer for 1 hour. This process is carried out for a total of 3 cycles (15 minutes at room temperature → 85℃, 1 hour → 15 minutes at room temperature → -40℃, 1 hour), and there is no change in the appearance of the plating film or the shape of the molded product before and after the test. Examined. Peeling strength: Peel off the plating film from a square plate (126 mm x 75 mm, 3 mm thick) plated with matte copper to a thickness of 25 to 40 μ over a length of 80 mm with a width of 25 mm, and calculate the average Peel strength was measured. Since the peeling load varies depending on the thickness of the plating film, the peeling strength when the plating film thickness is 30 μm was determined from the following formula. P: Pt (30/t) 3/4W (Kg/cm) P: Peeling strength (Kg/cm) pt: Average peeling load (Kg) t: Plating film thickness (μ) W: Peeling width (cm) Physical properties : Physical property values such as impact strength were determined in accordance with ASTM test methods. (1/2″IZOD: ASTMD256) Viscosity: The viscosity of the organosilicon compound was measured using an Ubbelohde viscosity tube. (JIS-K2283, 1969) The measurement temperature was 25 ± 0.1°C. Examples 1- 8 The parts in the examples indicate parts by weight.Polybutadiene latex "BR-1" (Toray Co., Ltd.)
Co., Ltd., average particle size 0.36μ), sodium pyrophosphate,
Glucose and ferrous sulfate were charged into 20 reaction vessels with the composition shown in Table 1. The temperature was raised to 60°C, a chain transfer agent, a monomer, and an emulsified oil-soluble initiator were continuously added, and polymerization was completed in 7 hours. After adding an antioxidant, the polymerized latex was coagulated with sulfuric acid, neutralized with caustic soda, filtered, washed, dehydrated, and dried to recover a uniform powder (hereinafter referred to as PB-1). Styrene-butadiene copolymer latex
SBR-1 (stainless steel content 25%, average particle size 0.60μ)
was used. Polymerization was carried out under the same graft polymerization conditions as in the case of using BR-1 and post-treated in the same manner to obtain a uniform powder (hereinafter referred to as SB-1). Hereinafter, SB-2 to SB-5 were obtained by changing the charging composition as shown in Table 1 under the same graft polymerization conditions. The styrene-butadiene copolymer latexes SBR-2, SBR-3, SBR-4, and SBR-5 were as follows. SBR-2: Styrene content 25%, average particle size 0.37μ SBR-3: 12%, 0.56μ SBR-4: 40%, 0.68μ SBR-5: 55%, 0.28μ Diluent resin The composition is bulk polymerized styrene/acrylonitrile copolymer (SAN-1) (manufactured by Toray Industries, Inc.).
AN/S=28/72) was used. As an organosilicon compound, Toray silicone
"SH-200" manufactured by Co., Ltd. (polydimethylsiloxane, viscosity 30,000 CS) was used. 0.5 of this stuff in toluene
% surface tension was 24.8 dyn/cm. Table 2 shows the blending ratio of the resin compositions used in the evaluation and the evaluation results. Example 9 As an organosilicon compound, Toray Silicone Co., Ltd.
manufactured by “SF8418” (carboxymethyl modified, viscosity
A resin composition was obtained in the same manner as in Example 1 except that 2500CS) was used. SF−8418 in toluene 0.5%
The surface tension of was 25.0 dyn/cm. The evaluation results are shown in Table 3. Example 10 As an organosilicon compound, Toray Silicone Co., Ltd.
manufactured by “SF8421” (epoxy polyether modified, viscosity
A resin composition was obtained in the same manner as in Example 1 except that 3500CS) was used. The surface tension of 0.5% SF8421 in toluene is
It was 25.4 dyn/cm. Example 11 As an organosilicon compound, Toray Silicone Co., Ltd.
A resin composition was obtained in the same manner as in Example 1, except that "SH-1107" (methylhydrodiene polysiloxane, viscosity 30CS) manufactured by Co., Ltd. was used. The surface tension of SH-1107 in 0.5% toluene is
It was 26.1 dyn/cm. Example 12 As an organosilicon compound, the viscosity at 25℃ is
It is 350CS. A resin composition was obtained in the same manner as in Example 1 except that a resin composition having the following repeating units was used. (Here, the molar ratio of x and y was x:y = 98:2.) The surface tension of this material at 0.5% in toluene is
It was 25.1 dyn/cm. Example 13 As an organosilicon compound, Toray Silicone Co., Ltd.
"FS-1265" (fluorine-modified oil, viscosity
A resin composition was obtained in the same manner as in Example 1 except that 1000CS) was used. The surface tension of FS−1265 in 0.5% toluene is
It was 25.7 dyn/cm. Comparative Example 1 Butadiene copolymer alone (PB-1) was evaluated without adding any organosilicon compound. The evaluation results are shown in Table 4. The plating film heat cycle resistance of this product was extremely poor. Comparative example 2 Styrene-butadiene copolymer alone (SB-1)
Evaluation was made by adding 0.05 part of "SH-200" to 100 parts. The surface of the plating film on this product was cloudy and the impact resistance was low. Comparative example 3 Styrene-butadiene copolymer alone (SB-2)
Evaluation was made by adding 0.05 part of "SH-200" to 100 parts. This material had excellent plating properties, but poor impact resistance. Comparative Example 4 0.005 part of "SH-200" was added to 100 parts of a combination system of polybutadiene copolymer (PB-1) and styrene-butadiene copolymer (SB-1). The plating film heat cycle resistance of this product was poor. Comparative Example 5 “SH-200” in 100 parts of PB-1 and SB-1 combination system
1.0 part of was added. The plating film surface of this product is partially uneven;
The adhesion strength of the plating film was also low. Comparative Example 6 “SH-200” was added to 100 parts of styrene-butadiene copolymer alone (SB-3) with a styrene content of 12%.
0.05 part was added. The surface of the plating film was cloudy. Comparative Example 7 0.05 part of SH-200 was added to 100 parts of styrene-butadiene copolymer alone (SB-4) with a styrene content of 40%. The surface of the plating film on this product was cloudy, and the impact resistance was extremely low. Comparative Example 8 As styrene-butadiene rubber latex
SBR-5 (styrene content 55%, average particle size 0.28μ) was used. The graft polymerization conditions were the same as for PB-1 (SB-5). 0.05 part of SH-200 was added to 100 parts of a mixture of PB-1 and SB-5 blended at a ratio of 70/30. This material had excellent plating properties but low impact resistance. Comparative Example 9 As an organosilicon compound, the viscosity at 25℃ is
The following phenylmethyl heat-resistant oil, which is 500CS, was used. The surface tension of a 0.5% by weight solution of this material in toluene was 26.7 dyn/cm. (Here, the molar ratio of x and y was x:y=1:1.) Even if an organosilicon compound with a small decrease in surface tension was added, the heat cycle resistance of the plating film was not sufficiently improved. Ta.

【table】

【table】

[Table] Appearance No gloss Slightly no gloss
Glossy except near the gate Glossy

【table】

[Table] <Effects of the Invention> The resin composition for plating of the present invention has excellent plating film strength, heat cycle resistance, and peel strength, as well as good physical properties, particularly impact strength. Therefore, it is possible to obtain an excellent plated product that has no practical problems in both heat-resistant and general uses.

Claims (1)

[Scope of Claims] 1 (a) A graft copolymer (A) obtained by partially graft-polymerizing an aromatic monovinyl monomer and a vinyl cyanide monomer to 15 to 75 parts by weight of polybutadiene latex. 5 to 95 parts by weight and (b) styrene containing 5 to 45 parts by weight of styrene.
95 to 5 parts by weight of a graft copolymer (B) prepared by partially graft polymerizing an aromatic monovinyl monomer and a vinyl cyanide monomer to 15 to 75 parts by weight of a butadiene copolymer latex; c) A mixture of 0 to 85 parts by weight of a copolymer (C) obtained by copolymerizing 50 to 85 parts by weight of an aromatic monovinyl monomer and 50 to 15 parts by weight of a vinyl cyanide monomer ((A) )
+ (B) + (C) total 100 parts by weight) (d) The viscosity at 25°C is 10 to 100,000 centistokes, and the viscosity at 25°C of a 0.5% by weight solution in toluene is 25°C.
The surface tension at is 26.5 dyn/cm or less,
Compounding 0.01 to 0.5 parts by weight of an organosilicon compound having a repeating unit represented by the following formula (),
A resin composition for plating with excellent plating properties. (Here, R ₁ and R ₂ represent one or more groups selected from a hydrogen atom, an alkyl group, an aralkyl group, a carboxymethyl group, a polyether alkyl group, an epoxyalkyl group, a trifluoromethyl group, and a phenyl group, and n indicates an integer greater than or equal to 1.)