JPH04279659A - Polycarbonate resin composition - Google Patents

Abstract

PURPOSE:To obtain a polycarbonate resin composition having excellent chemical resistance, coating performance, moldability and processability and impact resistance, comprising a blend of polycarbonates having different molecular weights and a specific graft copolymer. CONSTITUTION:(A) 30-80 polycarbonate comprising A1: 30-90wt.% high-molecular weight polycarbonate having g45,000 weight-average molecular weight and A2: 70-10 pts.wt. low-molecular weight polycarbonate having 7,000-16,500 weight- average molecular weight in a ratio of the weight-average molecular weight of A2/the weight-average molecular weight of A1 of 0.03-0.37 is blended with (B) 15-60 pts.wt. graft copolymer obtained by subjecting an aromatic vinyl compound, a vinyl cyanide compound and optionally an unsaturated monomer copolymerizable with these compounds to graft copolymerization in the presence of a rubber-like hydrocarbon and (C) 0-40 pts.wt. copolymer obtained by copolymerizing an aromatic vinyl compound with a vinyl cyanide compound and an unsaturated monomer copolymerizable with these compounds.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention provides chemical resistance, paintability, moldability such as sheet molding, blow molding, etc., and This invention relates to a novel polycarbonate resin composition with excellent impact resistance.

0002

BACKGROUND OF THE INVENTION Polycarbonate resins have excellent mechanical properties, electrical properties, and heat resistance, but because they have a relatively high softening temperature, they have poor moldability. In order to improve this drawback, styrenic resins with excellent fluidity, such as
Improving molding processability by blending acrylonitrile-butadiene-styrene (ABS) resin (Japanese Patent Publication No. 38
-15225, etc.) are known. However, these compositions have drawbacks such as poor chemical resistance and paintability.

[0003] In order to improve these drawbacks, a method has been proposed in which AES resin or AAS resin, which is a graft copolymer using ethylene-propylene rubber or acrylic rubber with high chemical resistance, is blended. 47-4
1424, Japanese Patent Publication No. 51-24540, Japanese Patent Application Laid-open No. 59-30849). Furthermore, JP-A-63-14
Publication No. 6960 discloses a method using a maleimide resin. However, these compositions have not been sufficiently improved in chemical resistance or paintability, and when used after painting, they may cause poor appearance on the surface of the molded product, or
This was not satisfactory because the mechanical properties deteriorated.

On the other hand, JP-A-2-129260 discloses that in a composition of a polycarbonate resin and a graft copolymer, the low-temperature impact resistance can be improved by increasing the molecular weight of the polycarbonate. However, the molecular weight of the polycarbonate in this example was approximately 41,000, and a polycarbonate having a weight average molecular weight of this level was not sufficiently effective in improving chemical resistance and paintability.

[0005] Furthermore, JP-A No. 63-43949 discloses a method for improving the balance between moldability and impact resistance by using a mixture of two types of polycarbonates with different intrinsic viscosities as the polycarbonate resin. There is. However, this publication uses a small amount of medium-molecular-weight polycarbonate and low-molecular-weight polycarbonate, so although moldability is excellent, the effect of improving impact resistance is small, and chemical resistance and paintability are poor. It was something.

[0006] Regarding this medium molecular weight polycarbonate, the specification only states that the intrinsic viscosity is 0.5 or more, preferably 0.55 or more, but does not state the upper limit thereof. Furthermore, there is no description of changes in performance of the composition when the molecular weight increases. Even in the examples, only one example in which polycarbonate has an intrinsic viscosity of 0.59 is described. The same applies to low molecular weight polycarbonate, and the specification states that the intrinsic viscosity is less than 0.5, preferably 0.45 or less, but the lower limit is not stated, and if the molecular weight of the polycarbonate becomes small. There is no mention of any changes in the performance of the composition.

[0007] Also, in the examples, only one example in which polycarbonate has an intrinsic viscosity of 0.44 is described. Therefore, although the amounts of the two components used in the two different polycarbonate mixtures disclosed in the publication are clear, the molecular weights of each component are extremely unclear, and the relationship between the molecular weights of the two components remains unclear. It has become. Furthermore, compositions of polycarbonate resin and graft copolymers with excellent fluidity have a problem in that the molten resin tends to sag (drawdown) when molded products are obtained by sheet molding or blow molding. Ta.

[0008]

[Problems to be Solved by the Invention] The present invention provides a composition of a polycarbonate resin and a graft copolymer, which has excellent chemical resistance and paintability, as well as good sheet formability and blow moldability. It is an object of the present invention to provide a resin composition that also has excellent impact resistance.

[0009]

[Means for Solving the Problems] As a result of intensive studies on the above-mentioned problems, the present inventors have found that it is important to use a polycarbonate mixture having a specific molecular weight ratio in the polycarbonate resin. Furthermore, by using a polycarbonate that is a mixture of high molecular weight polycarbonate and low molecular weight polycarbonate in a specific weight ratio, it has excellent chemical resistance, paintability, and impact resistance, and has a high heat distortion temperature. The present invention was based on the discovery that it is possible to obtain such a composition that maintains good moldability.

That is, the present invention provides (A) (a1) 30 to 90 parts by weight of a high molecular weight polycarbonate having a weight average molecular weight of 45,000 or more, and (a2) a weight average molecular weight of 7.
,000 to 16,500, and the ratio of weight average molecular weight of (a2)/weight average molecular weight of (a1) is 0.03.
0.37 to 30 to 80 parts by weight of polycarbonate, and (B) in the presence of rubbery polymer (b), an aromatic vinyl compound, a vinyl cyanide compound, and optionally copolymerizable with these. 15 to 60 parts by weight of a graft copolymer obtained by graft copolymerizing an unsaturated monomer, and (C) an aromatic vinyl compound, a vinyl cyanide compound, and, if necessary, an unsaturated monomer copolymerizable with these. It relates to a polycarbonate resin composition comprising 0 to 40 parts by weight of a copolymer obtained by copolymerizing.

The present invention will be explained in more detail below. The polycarbonate used in the present invention has the following general formula (
I)

0012

It has the structure shown below. In general formula (I), Y is -Bz-R or -ArOH, Z is -OH or -O
-CO-O-Bz-R, (in the above formula, Bz is a benzene ring, R is a hydrogen atom or an alkyl group, Ar is an aromatic residue, n is a polymer whose weight average molecular weight is 7,000 to 5
It is an integer that equals 00,000. When R is an alkyl group, the alkyl group is, for example,

0013
]

[Chemical formula 2] etc. can be mentioned. Furthermore, as Ar, for example,

[0014]

embedded image (m=3 to 11, the hydrogen atom of -(CH2)- may be substituted with a lower alkyl group, an aryl group, a halogen, etc.)

[0015]

Among these, the above (a) is particularly preferred, and especially in the general formula (I),

[0016]

Those containing 85 mol% or more of the repeating unit represented by the following formula are preferable.

Regarding the molecular weight of the polycarbonate resin used in the present invention, high molecular weight polycarbonate (a1)
and a low molecular weight polycarbonate (a2), or a medium molecular weight polycarbonate (a3) is added to the mixture.
) are further used in combination. The molecular weight of (a1) is determined by gel permeation chromatography (hereinafter referred to as GP).
Weight average molecular weight (hereinafter abbreviated as Mw)
That's over 45,000. Preferably 45,000
~500,000, more preferably 45,000~3
00,000.

When Mw is less than 45,000, the effect of improving chemical resistance, paintability, heat distortion temperature and impact resistance is small. When Mw exceeds 500,000, the effect of improving moldability gradually decreases. The molecular weight of (a2) is G
Mw by PC is 7,000 to 16,500. Preferably it is 10,000 to 16,500. When Mw is less than 7,000, the effect of improving impact resistance and heat distortion temperature is small. When Mw exceeds 16,500, the effect of improving moldability is small.

Furthermore, in the present invention, (a1) and (a2
) is important. Mw/(a2) of (a2)
1) It is necessary that Mw is in the range of 0.03 to 0.37 in order to improve moldability. Traditionally,
When producing a composition with a graft copolymer using polycarbonate having a high molecular weight, it was believed that the higher the molecular weight of the polycarbonate or the higher the content, the lower the moldability.

However, in the present invention, the polycarbonate having a very high molecular weight, which is the component (a1), is
Even if it is blended in a large amount of 0 parts by weight, the molecular weight of component (a2) is significantly different from that of component (a1), that is, the ratio of Mw of (a2)/Mw of (a1) is 0.
03 to 0.37, this combination of molecular weights will increase the SR value (ratio of the orifice diameter to the composition diameter) when measuring the melt flow index, and the Since the properties are significantly improved, the composition has excellent moldability such as blow moldability and sheet moldability. Moreover, a composition with excellent chemical resistance, paintability, impact resistance, and high heat distortion temperature can be obtained.

[0021] If this Mw ratio exceeds 0.37, the effect of the low molecular weight component (a2) decreases, resulting in poor moldability. If the Mw ratio is less than 0.03, properties such as impact resistance and chemical resistance will be poor. In addition, in order to further improve the impact resistance without significantly reducing the moldability of the (a1) and (a2) components, we added medium molecular weight polycarbonate (a3) to the (a1) and (a2) components.
can be added further. The molecular weight of (a3) is
17,000-35,000, preferably 20,000
~25,000.

(a1), (with the above specific molecular weight)
The usage ratio of (a2) and (a3) is that (A) component is (
When consisting of a1) and (a2), the amount of (a1) is 30 to 90 parts by weight, preferably 40 to 90 parts by weight, (
The amount of a2) is 70 to 10 parts by weight, preferably 59 to 1
It is 0 parts by weight. If (a1) is less than 30 parts by weight, impact resistance, chemical resistance and paintability will be reduced. If (a1) exceeds 90 parts by weight, moldability deteriorates. (a2
) is less than 10 parts by weight, the effect of improving moldability is small, and if it exceeds 70 parts by weight, impact resistance, chemical resistance and paintability are reduced.

When using component (a3), the amount of (a1) is 10 to 90 parts by weight, the amount of (a2) is 10 to 90 parts by weight, and the amount of (a3) is 10 to 50 parts by weight. Department. In order to improve impact resistance without significantly reducing moldability, the amount of (a3) is 10 to 50 parts by weight.

[0024] There are no particular restrictions on the method for producing the high-molecular weight and low-molecular weight polycarbonate resins used in the present invention, but for example, a method of polymerizing a crystallized polycarbonate prepolymer in a solid phase (for example, Japanese Patent Application Laid-Open No. 1-158033
(method described in Japanese Unexamined Patent Application Publication No. 1-271426)
is preferred.

In this solid phase polymerization method, for example, a crystallized aromatic polycarbonate prepolymer having a hydroxyl group and an aryl carbonate group as terminal groups is made to have a high molecular weight in a solid phase. The proportion of aryl carbonate group terminals in the
~80 mol%, and the weight average molecular weight is 6,
000 to 10,000 and the crystallinity is preferably 10 to 40%. Furthermore, when obtaining a high molecular weight polycarbonate, a polycarbonate resin having a weight average molecular weight of 45,000 to 500,000 obtained by solid phase polymerization is preferred.

The rubbery polymer (b) in component (B) used in the present invention is a polymer having elastomer properties in order to improve the impact resistance of the composition of the present invention. Examples of such polymers include diene polymers such as polybutadiene, styrene-butadiene rubber, butadiene-isoprene rubber, polyisobutylene, polyalkyl acrylates and polyalkyl methacrylates having an alkyl group having 1 to 10 carbon atoms.

Rubber-like polymers obtained by copolymerizing alkyl acrylate with butadiene, styrene, acrylonitrolyl, alkyl methacrylate, etc. can also be used. Furthermore, other graft-copolymerizable hydrogenated polymers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, styrene-butadiene block copolymers, silicone rubber, etc. can also be used.

Component (B) contains an aromatic vinyl compound, a vinyl cyanide compound, and, if necessary, an unsaturated monomer copolymerizable with these as monomers to be graft copolymerized with this rubbery polymer. It is a graft copolymer. The aromatic vinyl compound used in this graft copolymerization is
For example, styrene, α-methylstyrene, halogenated styrene, alkylated styrene, etc. are used, and these may be used in combination. Among these, styrene is preferred.

Further, as the vinyl cyanide compound, for example, acrylonitrile, methacrylonitrile, etc. are used. Among these, acrylonitrile is preferred. In addition, unsaturated monomers copolymerizable with these monomers include polyalkyl acrylates and polyalkyl methacrylates having alkyl groups having 1 to 10 carbon atoms, α,
Examples include β-unsaturated carboxylic acid and maleic anhydride, and these may be used in combination. Among these, methyl methacrylate and butyl acrylate are preferred.

The graft copolymer (B) comprises 5 to 50% by weight, preferably 10 to 40% by weight of the above rubbery polymer, 10 to 95% by weight of an aromatic vinyl compound, and 5 to 50% by weight of a vinyl cyanide compound. % and, if necessary, 0 to 40% by weight of a copolymerizable unsaturated monomer. If the proportion of the rubbery polymer is less than 5% by weight, the resulting composition will not have sufficient impact resistance;
If it exceeds 50% by weight, moldability and thermal stability will deteriorate. Graft copolymerization to the rubbery polymer is carried out by known polymerization methods such as emulsion polymerization, suspension polymerization, and bulk polymerization.

The aromatic vinyl copolymer which is component (C) of the present invention is copolymerized using an aromatic vinyl compound, a vinyl cyanide compound and, if necessary, an unsaturated monomer copolymerizable with these. Polymerized. Examples of the aromatic vinyl compound used in this copolymerization include styrene, α-methylstyrene, halogenated styrene, and alkylated styrene, and these may be used in combination. Among these, styrene is preferred.

[0032] As the vinyl cyanide compound, for example, acrylonitrile, methacrylonitrile, etc. are used. Among these, acrylonitrile is preferred. In addition, unsaturated monomers copolymerizable with these monomers, such as polyalkyl acrylates and polyalkyl methacrylates having alkyl groups having 1 to 10 carbon atoms, α,β-unsaturated carboxylic acids, maleic anhydride, etc. These may be used in combination. Among these, methyl methacrylate and butyl acrylate are preferred.

The proportions of the components constituting the composition of the present invention are:
Composition consisting of 30 to 80 parts by weight of polycarbonate resin (A), 15 to 60 parts by weight of graft copolymer (B), and 0 to 40 parts by weight of aromatic vinyl copolymer (C), for a total of 100 parts by weight. It is a thing. Polycarbonate resin (A)
However, if it is less than 30 parts by weight, the chemical resistance of the composition of the present invention will be poor, and if it exceeds 90 parts by weight, moldability will be reduced. The graft copolymer (B) needs to be used in an amount of 15 to 60 parts by weight in order to make the composition excellent in impact resistance. If it is less than 15 parts by weight, the impact resistance will decrease, and if it exceeds 60 parts by weight, the heat distortion temperature and moldability will decrease.

The aromatic vinyl copolymer (C) is added to adjust the amount of rubbery polymer in the composition, and when the amount of rubbery polymer in component (B) is small. does not need to be blended. When the proportion of component (C) exceeds 40 parts by weight, impact resistance decreases.

[0035] The method for blending the composition of the present invention is not particularly limited, and can be done by mixing powders and granules using a known technique such as a Henschel mixer, tumbler, blender, etc., and then mixing the mixture with an extruder, kneader, or It can be produced by various methods, such as melt-mixing using a mixer or the like, sequentially mixing a pre-melted resin with other resins, and directly molding a mixture of each component using an injection molding machine. In order to obtain a molded article from the resin composition of the present invention, dyes, pigments, light stabilizers, plasticizers, antistatic agents, flame retardants, flame retardant aids, etc. are mixed in advance to the extent that their physical properties are not impaired. Good too.

[0036]

[Example] The present invention will be specifically explained in the following example.
These are not intended to limit the scope of the invention. In addition,
The physical properties of the compositions shown in the Examples and Comparative Examples below were determined as follows.

(1) Molecular Weight The weight average molecular weight (Mw) value measured by gel permeation chromatography (GPC) was used. (2) Tensile strength and elongation Measured according to ASTM D-638.

(3) Izod impact strength ASTM D
-256 (notched thickness 1/4 inch). (4) Heating distortion temperature Measured according to ASTM D-648. (5) Melt flow index (MFR) JIS
It was measured according to the K7210 B method (240°C, 10 kg load).

(6) Evaluation of sheet molding processability A sheet having a length of 100 cm, a width of 30 cm, and a thickness of 4 mm was molded by an extrusion sheet molding method. In this evaluation of sheet formability, a molded product with no drawdown and an excellent discharge rate was evaluated as ○, and a molded product with an excellent discharge rate was evaluated as ×.

[0040] The sheet formability is determined according to the melt flow index (MFR) JIS K7210B method (2
40°C, 10 kg load), the ratio of the diameter (r1) of the resin composition piece obtained by melting 10 seconds after the start of MFR measurement of the composition and the orifice nozzle diameter (r0) r1 /
There was a correlation between the value of r0 and the sheet molding processability. ○: When SR is a value of 1.3 or more ×: When SR is a value of less than 1.3

(7) Paint test A paint (high urethane N
o5000 (manufactured by NOF) was spray-painted, and the appearance and tensile test after painting were conducted.

Reference Example 1 Production of high molecular weight polycarbonate (a1-1) 2,2
- Put 130 parts by weight of bis(4-hydroxyphenyl)propane and 129 parts by weight of diphenyl carbonate into a reaction tank, and after flowing a nitrogen stream of 100 Nl/hr at 230°C for 3.5 hours, gradually increase the temperature over 1.5 hours. Then, the degree of vacuum was lowered to 3 mmHg, and the mixture was stirred in that state for 1 hour to react and obtain a prepolymer.

The molecular weight was 8,100, and the ratio of hydroxy terminals to all polymer terminals was 48 mol%. This prepolymer was then directly dissolved in acetone at 200%
The prepolymer was immersed in a portion by weight for crystallization, then filtered and dried to obtain a powdery prepolymer. The prepolymer was placed in a turnbull dryer and rotated while flowing a nitrogen stream at a rate of 10 Nl/hr to reduce the pressure to 2 to 3 mmHg.
The temperature was gradually raised to perform solid phase polymerization at 220° C. for 16 hours to obtain polycarbonate powder. The weight average molecular weight of the obtained polycarbonate was 56,000.

Reference Example 2 Production of High Molecular Weight Polycarbonate (a1-2) A polycarbonate having a weight average molecular weight of 50,000 was obtained in the same manner as in Reference Example 1 except that the polymerization time was changed to 15 hours.

Reference Example 3 Production of high molecular weight polycarbonate (a1-3) A polycarbonate having a weight average molecular weight of 86,000 was obtained in the same manner as in Reference Example 1 except that the polymerization time was 20 hours.

Reference Example 4 Production of high molecular weight polycarbonate (a1-4) 2,2
- 130 parts by weight of bis(4-hydroxyphenyl)propane, 129.2 parts by weight of diphenyl carbonate and 1
, 3,5-Tris[α,α'-dimethyl-4-hydroxyphenyl]benzene was used in the same manner as in Reference Example 1, except that 0.8 parts by weight of benzene was used, to prepare an aromatic polycarbonate powder having a weight average molecular weight of 260,000. Obtained.

Reference Example 5 Production of low molecular weight polycarbonate (a2-1) The weight average molecular weight was 1 in the same manner as in Reference Example 1 except that a prepolymer with 26% hydroxyl terminals was used and the polymerization time was 4 hours.
6,000 polycarbonates were obtained.

Reference Example 6 Production of low molecular weight polycarbonate (a2-2) The weight average molecular weight was 1 in the same manner as in Reference Example 1 except that a prepolymer with 26% hydroxyl terminals was used and the polymerization time was 3 hours.
0,000 polycarbonate was obtained.

Reference Example 7 Production of low molecular weight polycarbonate (a3-1) The weight average molecular weight was 2 in the same manner as in Reference Example 1 except that a prepolymer with 30% hydroxyl terminals was used and the polymerization time was 7 hours.
0,000 polycarbonate was obtained.

Reference Example 8 Production of Graft Copolymer (B-1) 750 parts by weight of butadiene latex having an average particle diameter of 0.30 μm (40% by weight in terms of rubber) and 1 weight of emulsifier (disproportionated potassium rosinate) 200 parts by weight of acrylonitrile, 500 parts by weight of styrene, 0.8 parts by weight of cumene hydroperoxide, and 0.7 parts by weight of t-dodecyl mercaptan. 1.0 parts by weight of sodium formaldehyde sulfoxylate and 0.10 parts by weight of ferrous sulfate (FeSO4.7H2O) in a mixed solution of 500 parts by weight of distilled water.
Polymerization was carried out by adding over 6 hours an aqueous solution in which parts by weight and 0.2 parts by weight of ethylenediaminetetraacetic acid/2Na salt were dissolved.

After the addition was completed, stirring was continued for another 2 hours to complete the polymerization. The polymerization rate was 94%. The resulting graft copolymer latex was coagulated with a dilute aqueous sulfuric acid solution, washed, dehydrated, and dried to obtain white powder (B-1).

Reference Example 9 Production of Copolymer (C-1) 0.4 parts by weight of potassium persulfate and 2.0 parts by weight of potassium rosinate were added to 180 parts by weight of water and dissolved, and 70 parts by weight of styrene was added to this aqueous solution. 1, 30 parts by weight of acrylonitrile and 0.2 parts by weight of dodecyl mercaptan were added, and the mixture was reacted at 70° C. for 4 hours to obtain an aromatic vinyl copolymer. The polymerization rate was 94%. The produced copolymer is coagulated with a dilute aqueous sulfuric acid solution, washed, dehydrated, and dried to form a white powder (
C-1) was obtained.

Example 1 50 parts by weight of polycarbonate as component (A) ((a1
-1) 30 parts by weight and (a2-1) 20 parts by weight),
After mixing 30 parts by weight of component (B) and 20 parts by weight of component (C) using a Henschel mixer, the mixture was made into pellets using an extruder. A test piece was prepared by molding this pellet using an injection molding machine. In addition, sheet processability was evaluated using a sheet molding method.

Examples 2 to 8 Pellets were prepared according to the formulations shown in Table 1, and test pieces were prepared using an injection molding machine and their physical properties were evaluated. The results are shown in Table 3.

Comparative Examples 1 to 5 Pellets were prepared using the formulations shown in Table 2, and test pieces were prepared using an injection molding machine and their physical properties were evaluated. The results are shown in Table 3. In addition, polycarbonate resins having the following molecular weights were used for blending. 1) Polycarbonate resin (PC-1) Weight average molecular weight: 27,000 2) Polycarbonate resin (PC-2) Weight average molecular weight: 19,500 From the comprehensive evaluation in Table 3, the composition of the present invention is made of impact-resistant material (Izod), It can be seen that the molding processability ((MFR) and (SR)), chemical resistance, and paintability (change in tensile strength before and after painting) are excellent, and a good balance of physical properties is exhibited.

[0056]

[Table 1]

[0057]

[Table 2]

[0058]

[Table 3]

[0059]

Effects of the Invention: A composition comprising a graft copolymer and a blend of polycarbonates with different molecular weights containing the high molecular weight polycarbonate of the present invention has excellent chemical resistance, paintability, sheet moldability, and blow moldability. It has the effect of having excellent moldability and impact resistance.

Claims (2)

[Claims] Claim 1: (A) (a1) Weight average molecular weight 45
,000 or more high molecular weight polycarbonate 30-9
0 parts by weight and (a2) weight average molecular weight 7,000-16
, 500, and the weight average molecular weight of (a2)/(a
1) 30 to 80 parts by weight of polycarbonate having a weight average molecular weight ratio in the range of 0.03 to 0.37, and (B)
15 to 60 weight of a graft copolymer obtained by graft copolymerizing an aromatic vinyl compound, a vinyl cyanide compound, and optionally an unsaturated monomer copolymerizable with these in the presence of the rubbery polymer (b). (C) an aromatic vinyl compound,
A polycarbonate resin composition comprising a vinyl cyanide compound and, if necessary, 0 to 40 parts by weight of a copolymer obtained by copolymerizing an unsaturated monomer copolymerizable with the vinyl cyanide compound. Claim 2: (A) (a1) Weight average molecular weight 45
,000 or more high molecular weight polycarbonate 10-9
0 parts by weight and (a2) weight average molecular weight 7,000-16
, 500 and (a3) a weight average molecular weight of 17,000 to 35,
000, and the weight average molecular weight of (a2)/(a1
30 to 80 parts by weight of polycarbonate having a weight average molecular weight ratio of 0.03 to 0.37; and, if necessary, 15 to 60 parts by weight of a graft copolymer obtained by graft copolymerizing an unsaturated monomer copolymerizable with these, and (C) an aromatic vinyl compound, a vinyl cyanide compound, and, if necessary, A polycarbonate resin composition comprising 0 to 40 parts by weight of a copolymer obtained by copolymerizing these with an unsaturated monomer that can be copolymerized.