JPH02202937A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:To obtain the title composition which can improve the adhesion of topcoating material and the impact strength, etc., of a molding by mixing polypropylene with a specified ethylene copolymer elastomer and a polyolefin modified with an unsaturated carboxylic acid (derivative) in a specified ratio. CONSTITUTION:A polypropylene resin composition is produced by mixing 50-90wt.% polypropylene (A) with 8-35wt.% copolymer elastomer (B) of ethylene with an unsaturated carboxylic acid (e.g. maleic acid) and an alpha,beta-ethylenically unsaturated carboxylic ester (e.g. methyl methacrylate) and 0.2-30wt.% polyolefin (C) modified with an unsaturated carboxylic acid (derivative) (e.g. maleic anhydride-modified polypropylene). As component B, a copolymer elastomer consisting of 5-95wt.% ethylene units, 1-40wt.% unsaturated carboxylic acid units and 4-94wt.% alpha,beta-ethylenically unsaturated carboxylic acid ester units is suitable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel polypropylene resin composition. More specifically, the present invention is suitable as a material for painting applications such as painted bumper materials, can be overcoated without undercoating with a primer, has excellent film adhesion of the topcoat paint, and has high impact resistance. The present invention relates to a polypropylene resin composition having strength.

[Prior Art] Conventionally, polypropylene resin has been known to be chemically inert because it does not have a polar group in its molecule and has extremely poor paintability. For painted bumpers made of polypropylene resin, which are in increasing demand, a method is used in which a primer is applied as an undercoat and then a polyurethane paint is applied on top of the undercoat to improve the adhesion of the topcoat.

However, this method has problems such as increasing the number of steps and lengthening the time it takes to finish the product, as well as high paint costs. Attempts are being made.

Conventional techniques related to primerless painting of polypropylene resin bumpers include, for example, (1) plasma treatment method (Japanese Patent Application Laid-open No. 57-207625, 5g
-208337 to 208339, 59-109
No. 530 L(2) Method of grafting polar groups to polypropylene (JP-A No. 62-64848, No. 62-62-
119243) and (3) a method of blending a polar substance with polypropylene (Japanese Unexamined Patent Publications Nos. 51-145553 and 61-89239).

However, although the plasma treatment method described in (1) above provides high coating film adhesion, it has high equipment costs, poor process flow, and the plasma treatment may not be uniform. It has disadvantages, and (2
) In the method of grafting polar groups to polypropylene and polypropylene, the monomers used may be toxic, sufficient coating film adhesion may not be obtained, and the weather resistance and other physical properties of the composition may deteriorate. There are problems such as not being able to escape.

Furthermore, as for the method (3) of blending a polar substance with polypropylene, for example, a partially crosslinked mixture of polypropylene resin kneaded with ethylene copolymer rubber and an ethylene-acrylic acid ester copolymer may be blended. A composition comprising a polyolefin and an unsaturated dicarboxylic acid-modified polymer (Japanese Unexamined Patent Publication No. 61-89239) has been disclosed. However, all of these compositions do not necessarily have sufficient paint film adhesion as bumper materials for brimerless painting, and have not yet been put to practical use.

Therefore, the inventors of the present invention have conducted extensive research and have found (a) polypropylene, which is suitable as a material for primerless coating.
(b) A two-component crystalline copolymer of ethylene and an unsaturated carboxylic acid, or a modified product obtained by blending EPR with this two-component crystalline copolymer and crosslinking with peroxide; )
A polypropylene resin composition containing modified polyolein has been discovered. However, although the composition can be suitably used as a primerless coating material,
It is not always possible to satisfy both the physical properties of paint film adhesion and impact strength at the same time.

[Problems to be Solved by the Invention] The present invention overcomes the drawbacks of the prior art regarding primerless coating of polypropylene resin materials such as bumper materials, and enables topcoating without undercoating with a primer. In addition, it is possible to provide a molded product with excellent adhesion of the topcoat paint and high impact strength, and it is a polypropylene resin composition suitable for use as a material for various polypropylene coatings, including polypropylene bumper materials for painting. It was done for the purpose of providing something.

[Means for Solving the Problems] The present inventor has developed a polypropylene resin composition having the above-mentioned excellent characteristics (as a result of extensive research, it has been found that polypropylene contains ethylene, unsaturated carboxylic acid and α9β-ethylenic acid). It was discovered that this objective could be achieved by a composition comprising a copolymerized elastomer with an unsaturated carboxylic acid ester and a polyolefin modified with an unsaturated carboxylic acid or its derivatives, each in a predetermined ratio. Based on this, the present invention was completed.

That is, the present invention provides (A) polypropylene 50 to 90
Weight %, (B) Ethylene and unsaturated carboxylic acid and α, β-
8 to 35% by weight of a copolymerized elastomer with an ethylenically unsaturated carboxylic acid ester and (C) a polyolefin modified with an unsaturated carboxylic acid and/or a derivative thereof.
The object of the present invention is to provide a polypropylene resin composition containing 2 to 30% by weight of polypropylene.

The present invention will be explained in detail below.

In the composition of the present invention, the polypropylene used as component (A) includes, for example, an isotactic propylene homopolymer having crystallinity, a copolymer part consisting of an ethylene propylene random copolymer with a low content of ethylene units, or A substantially crystalline propylene block copolymer commercially available as a so-called propylene block copolymer composed of a homopolymer part made of a propylene homopolymer and a copolymer part made of an ethylene propylene random copolymer with a relatively high content of ethylene units. A substantially crystalline block copolymer of propylene and ethylene, or a block copolymer in which each homopolymer part or copolymer part in this block copolymer is further copolymerized with an a-olefin such as butene-1. Preferred examples include propylene-ethylene-σ-olefin copolymer.

Among these polypropylenes, Ml is 1009/1
0 minutes or less, particularly in the range of 1 to 509/10 minutes, is preferred.

In the composition of the present invention, a copolymerized elastomer of ethylene, an unsaturated carboxylic acid, and an α,β-ethylenically unsaturated carboxylic acid ester is used as the component (B). Examples of unsaturated carboxylic acids used in this copolymerized elastomer include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, hepmaric acid, itaconic acid, crotonic acid, isocrotonic acid, citraconic acid, sorbic acid, mesaconic acid, and angelic acid. Examples include acids, and these may be used alone or in combination of two or more. Also,
Examples of the σ,β-ethylenically unsaturated carboxylic acid esters include those having preferably 3 to 8 carbon atoms, such as acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, fumaric acid, itaconic acid, crotonic acid, and incrotonic acid. , β-ethylenically unsaturated carbonic acid, m-alcohols such as tomethyl alcohol, ethyl alcohol, isopropyl alcohol, and n-propyl alcohol, dihydric alcohols such as ethylene glycol and propylene glycol, and polyhydric alcohols such as glycerin and pentaerythritol. These esters may be used alone or in combination of two or more. Furthermore, the copolymerized elastomer of component (B) may optionally be a derivative of the unsaturated carboxylic acid, such as an acid anhydride,
Copolymers of amides, imides, metal salts, esters of unsaturated carboxylic acids other than α, β-ethylenically unsaturated carboxylic acids, etc. can also be used.

This copolymerized elastomer contains 5 to 95% by weight of ethylene units, preferably 20 to 85%! %, unsaturated carboxylic acid units 1-40% by weight, preferably 2-30% by weight, and a
, β-ethylenically unsaturated carboxylic acid ester units 4 to 9
Preferably, it contains 4% by weight, preferably 15 to 85% by weight, is randomly copolymerized, and has elastomeric properties.

The content of the ethylene unit is more than 95% by weight or α
, those containing less than 4% by weight of β-ethylenically unsaturated carboxylic acid ester units will not exhibit elastomer properties, and those containing less than 5% by weight of ethylene units, a, β-ethylenically unsaturated carboxylic acid ester units, etc. If the content exceeds 94% by weight, low-temperature impact properties tend to decrease, if the unsaturated carboxylic acid unit is less than 1% by weight, the paintability is poor, and if it exceeds 40% by weight, the elastomer properties are insufficient. .

In the present invention, the copolymerized elastomer of component (B) has a Mooney viscosity of 10 to 80 at a temperature of 100°C.
Particularly preferred are those having a tensile elongation of 500% or more and a glass transition temperature of 120°C or less.

In the composition of the present invention, a polyolefin modified with an unsaturated carboxylic acid and/or a derivative thereof is used as component (C). Examples of the polyolefin used for modification include polypropylene exemplified in the explanation of component (A) polypropylene, polyethylene, and ethylene-a.
-Olefin copolymer rubber, ethylene-α-olefin-
non-conjugated diene compound copolymer (e.g. EPDM etc.),
Ethylene-aromatic monovinyl compound-conjugated diene compound copolymer rubber or the like is used. In addition, examples of the a-olefin include propylene, butene-11pentene-
1, hexene-1,4-methylpentene-1, etc., and these may be used alone or in combination of two or more.

Further, unsaturated carboxylic acids used for modification include, for example, acrylic acid, methacrylic acid, maleic acid, fumaric acid,
itaconic acid, crotonic acid, citraconic acid, sorbic acid,
Examples include mesaconic acid, angelic acid, etc., and its derivatives include acid anhydrides, esters, amides, imides,
There are metal salts, such as maleic anhydride, itaconic anhydride, citraconic anhydride, methyl acrylate, methyl methacrylate, ethyl acrylate, butyl acrylate, maleic acid monoethyl ester, acrylamide, maleic acid monoamide, maleimide, N -butylmaleimide,
Examples include sodium acrylate and sodium methacrylate.

When modifying the above-mentioned polyolefin, these unsaturated carboxylic acids and their derivatives may be used alone or in combination of two or more, and there are no particular restrictions on the modification method, and known methods may be used. For example, a method in which the polyolefin is dissolved in a suitable organic solvent, an unsaturated carboxylic acid or a derivative thereof, and a radical generator are added, followed by stirring and heating, or a method in which each of the above components is dissolved in an extruder A method of graft copolymerization by supplying the polymer to

In the modified polyolefin used as component (C), the amount of unsaturated carboxylic acid or its derivative added is usually in the range of 0.2 to 15% by weight. If it is, it is usually 0.2 to 15% by weight, preferably O, S to 12% by weight, more preferably 1 to 8% by weight, ethylene-a-olefin copolymer rubber or styrene-ethylene-butadiene copolymer rubber. In the case of amorphous materials such as
．． It is selected in the range of 2 to 8% by weight, preferably 0.5 to 5% by weight.

Further, as component (C) in the composition of the present invention, only the polyolefin modified as described above may be used, or a mixture of this modified polyolefin and an unmodified polyolefin may be used as desired.

In the composition of the present invention, the content of (A) 1 ton polypropylene is 50 to 90% by weight, the content of the copolymerized elastomer as component (B) is 8 to 35% by weight, and the content of modified polyolefin as component (C) is 50 to 90% by weight. The content is 002-30% by weight
It is necessary to be within the range of . A more preferable composition ratio of the composition of the present invention is that component (A) is 60 to 85% by weight, component (B) is 10 to 30% by weight, and component (C) is 0.5 to 25% by weight. be.

If the content of component (A) is less than 50% by weight, mechanical properties such as rigidity will be poor, making it unsuitable for use as a bumper material, and if it exceeds 90% by weight, it will be difficult to obtain high coating film adhesion. Furthermore, if the content of component (B) is less than 8% by weight, sufficient paint film adhesion may not be obtained, and if it exceeds 35% by weight, mechanical properties such as rigidity may deteriorate, resulting in bumper materials, etc. becomes difficult to use as Furthermore, said (C)
If the content of the components is less than 0.2% by weight, component (A) and (B)
) component cannot be fully utilized, resulting in poor physical properties and coating adhesion, and if it exceeds 30% by weight, mechanical properties such as rigidity decrease, making it unsuitable for bumper materials, etc.

When the polypropylene resin composition is a binary system of component (A) and component (C), sufficient coating film adhesion cannot be obtained;
On the other hand, in the case of a binary system of components (A) and (B), high paint film adhesion and physical properties suitable for bumper materials etc. cannot be obtained.

The composition of the present invention may contain various additives, reinforcing materials,
Fillers, such as heat stabilizers, weather stabilizers, antistatic agents,
Lubricants, slip agents, nucleating agents, flame retardants, pigments, dyes, glass fibers, carbon fibers, talc, calcium carbonate, calcium sulfate, and the like can be added to the extent that they do not impair the purpose of the present invention.

There are no particular limitations on the method for producing the composition of the present invention, and methods commonly used for producing polypropylene resin compositions can be used.
The order of mixing the components can be freely selected as desired. For example, the required amounts of components (A), (B), (C) and various additive components used as necessary are mixed in a kneader such as a kneader roll or a Banbury mixer, or in a l-shaft or twin-shaft press. It can be manufactured by adding it all at once to a mixing machine and kneading it.

[Examples] Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

In addition, the abbreviations in the table mean the following contents.

PF'-1: ethylene-propylene copolymer, Manufactured by Idemitsu Petrochemical Co., Ltd. Product name J-765H.

M199/10 minutes (230°C), ethylene unit content 8.3 wL% EAA-1: Ethylene-acrylic acid copolymer, Mikata DuPont Polychemical Co., Ltd., trade name Nucrel N1560, M1609/10 minutes (190°C) ), acrylic acid unit content 15 wt% EAA-2: Carboxyl group-containing ethylene-acrylic dimethyl ester copolymer elastomer, manufactured by Showa Den Ni DuPont Co., Ltd., trade name Baymac G1 ML1+4 (100°C) 16 Modified PO-1: 1 in anhydrous form Pholic acid modified polypropylene, Idemitsu Petrochemical (
Co., Ltd., product name Polytac H-3000P.

Maleic anhydride addition amount 6 wt, %, Ml 100
9/10 minutes (230°C) Modified PO-2: Maleic anhydride modified ethylene-propylene random copolymer, manufactured by Sumitomo Chemical Co., Ltd., trade name Nisprene M-12031 Ethylene unit content 75 wt%, maleic anhydride addition amount 1 wt%, Ml 0.89/10 min (230°C) Modified PO-38 Maleic anhydride modified styrene-ethylene-butadiene copolymer, manufactured by Asahi Kasei Corporation, trade name Tuftic M1913, specific gravity 0.92, Ml 2 .29/10 minutes (230°C) EPR: Ethylene-propylene random copolymer, manufactured by Japan Synthetic Rubber Co., Ltd., trade name JSR-EPO7P.

Ethylene unit content 73wt%, MLl+4 (100℃) 70 Moreover, each characteristic was evaluated as follows.

(1) Paint film adhesion A cut with a width of 10 ma was made in the paint film, and the 180' peel strength was measured using Autograph DSC2000 manufactured by Shimadzu Corporation.

(2) Impact strength Measured by notched Izot impact test at 23°C in accordance with JISK-7110.

Furthermore, as a urethane paint, a mixture of R-273C (trade name: main agent) and R-271 (curing agent) manufactured by Nippon B Chemical Co., Ltd. in a weight ratio of 5:1, and the viscosity adjusted with thinner, was used. was used.

Examples 1 to 8, Comparative Examples 1 to 6 Each component of the type and amount shown in Table 1 was charged into an NVC-50 kneading extruder (manufactured by Nakatani Koki Co., Ltd.) and kneaded.
A polypropylene resin composition was prepared. In addition, EAA-
When using 2, a composition of a predetermined ratio is prepared by kneading PP with a Banbury mixer in advance, and then using the granulated pellets in the kneading extruder.

Next, this composition was injection molded to a size of 140X140X3m.
A molded product of 1.1.m was prepared, then washed with 1-trichloroethane vapor for 30 seconds, degreased and then sprayed directly with urethane paint without applying a primer. The coating was performed by baking at 80°C for 30 minutes. Table 1 shows the results of measuring each characteristic.

〔Effect of the invention〕

The polypropylene resin composition of the present invention can be overcoated without undercoating a brimer, and can provide a molded product with excellent film adhesion of the b-coating paint and high impact strength, and can be used for painting. Various types of polypropylene coatings, including polypropylene bumper materials, are suitably used as materials.

Claims (1)

[Scope of Claims] 1 (A) 50 to 90% by weight of polypropylene, (B) 8 to 35% by weight of a copolymer elastomer of ethylene, unsaturated carboxylic acid, and α,β-ethylenically unsaturated carboxylic acid ester, and ( C) A polypropylene resin composition containing 0.2 to 30% by weight of a polyolefin modified with an unsaturated carboxylic acid and/or a derivative thereof. 2 The copolymerized elastomer of component (B) has 5 ethylene units.
~95% by weight, 1 to 40% by weight of unsaturated carboxylic acid units and 4 α,β-ethylenically unsaturated carboxylic acid ester units
The polypropylene resin composition according to claim 1, which contains 94% by weight.