JPS61272217A - Polyolefin resin composition - Google Patents

Abstract

PURPOSE:The titled composition, obtained by melt kneading a mixture prepared by adding a specific amount of a hydroxyalkyl (meth)acrylate to a polyolefin in the presence of an organic peroxide, capable of keeping the external appearance, etc., of the polyolefin and having improved adhesive properties, coating properties, etc. CONSTITUTION:A composition obtained by adding (B) 0.5-7pts.wt., preferably 1-5pts.wt. compound expressed by the formula (R is H or methyl; n is 1-22), e.g. 2-hydroxyethyl methacrylate, to (A) 100pts.wt. polyolefin, preferably crystalline polypropylene (PP), and melt kneading the resultant mixture in the presence of preferably 0.2-3.5pts.wt. organic peroxide, e.g., tert-butyl peroxybenzoate.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to mechanical and thermal properties, specific gravity,
This invention relates to a polyolefin resin composition that maintains surface scratch resistance, appearance, etc., and has excellent adhesiveness and paintability.

[Conventional technology]

Polyolefins such as polypropylene are non-polar resins and are difficult to adhere or paint.

As a solution, for example, surface treatments such as plasma treatment, corona discharge treatment, flame treatment, solvent treatment, and acid treatment can be applied to polypropylene molded products to generate polar groups such as carbonyl groups on the surface of the molded products. A method of imparting adhesiveness and paintability is known.

Also known is a method of mixing polypropylene with inorganic fillers such as talc and calcium carbonate, fillers such as wood flour, or other resin components such as EPR.

[Problem that the invention seeks to solve]

The above-mentioned surface treatment methods have problems such as requiring expensive surface treatment equipment, difficulty in waste disposal, and difficulty in uniform surface treatment depending on the shape of the molded product.

In addition, the method of mixing fillers or other resin components described above has problems such as poor scratch resistance on the surface of the molded product, noticeable poor appearance, increased specific gravity, worsened flowability, and decreased physical properties. There is.

Therefore, an object of the present invention is to provide a polyolefin resin composition that maintains the mechanical and thermal properties, specific gravity, surface scratch resistance, appearance, etc. of polyolefin, and has excellent adhesiveness and paintability.

[Means for solving problems]

As a result of various studies, the present inventors have developed a polyolefin resin composition that achieves the above objectives by melt-kneading a mixture of polyolefin and a specific monomer added in a specific amount in the presence of an organic peroxide. The present invention was achieved based on the finding that the following can be obtained.

That is, in the present invention, a mixture obtained by adding 0.5 to 7 parts by weight of a compound represented by the following general formula (I) to 100 parts by weight of a polyolefin is melt-kneaded in the presence of an organic peroxide. A polyolefin resin composition with excellent adhesiveness and paintability.

(In the above formula, R is a hydrogen atom or a methyl group, and n is 1 to 22.) The polyolefin resin composition of the present invention will be described in detail below.

Preferred polyolefins in the polyolefin resin composition of the present invention include crystalline propylene homopolymer and ethylene content of 0.5 to 20% by weight and MF+
(Melt flow index) 0.1-30 g/
In addition to crystalline polypropylene such as 10+win ethylene-propylene block copolymer, linear low-density polyethylene, high-density polyethylene, etc. may be mentioned, and the above-mentioned ethylene-propylene block copolymer is particularly preferred.

In addition, preferred compounds represented by the general formula (I) used in the polyolefin resin composition of the present invention include:
2-hydroxy ethyl methacrylate, 2-hydroxy ethyl acrylate, hydroxy propyl
Examples include methacrylate.

The amount of the compound represented by the general formula (1) to be added is 0.5 to 7 parts by weight, preferably 1 to 5 M parts, based on 100 parts by weight of the polyolefin.

If the amount of this compound added is less than 0.5 parts by weight, the effect of the addition will not be sufficient, and if it is more than 7 parts by weight, the appearance of the surface of the molded product will deteriorate.

Furthermore, the organic peroxide used in the polyolefin resin composition of the present invention is not particularly limited and may be appropriately selected depending on cost and required performance, such as t-butyl peroxy benzoate, dicumyl peroxide, oxide, 2,5-dimethyl-2,5-di<t-butyl peroxy)hexane, and the like.

The amount of this organic peroxide added is as follows:
Approximately 0.2 to 3.5 parts by weight is suitable for 0M parts.

Thus, the polyolefin resin composition of the present invention can be obtained as follows.

First, the compound represented by the general formula (I) and the organic peroxide are added to the polyolefin in the above proportions, and mixed using a mixer such as a Henschel mixer or a tumbler.

Next, this mixture is melt-kneaded using a single-screw extruder, a two-stage twin-screw extruder, or the like to obtain the polyolefin resin composition of the present invention.

The above melt-kneading is preferably carried out at a resin temperature of 170 to 250'C, although it varies depending on the type of polyolefin.

Due to the above-mentioned melt cross-fertilization, the polyolefin can be formed by the above-mentioned general formula (
It is graft-modified with the compound represented by 1).

The polyolefin resin composition of the present invention obtained as described above is usually used as a molding material in the form of pellets. Moreover, the polyolefin resin composition of the present invention preferably has a polyolefin graft modification amount of 0.2 to 3% by weight.

In addition, when adding the compound represented by the general formula (I) to the polyolefin, the polyolefin resin composition of the present invention may contain, for example, Irganox 1010 as an additive.
Clrgnox 1010), an antioxidant such as BHT, calcium stearate, etc. can be added.

In addition, other polymers such as unmodified polyolefin may be blended into the polyolefin resin composition of the present invention, depending on the purpose of use. It is preferable that the amount of the other polymer blended above is 90% by weight or less.

The polyolefin resin composition of the present invention is suitably used, for example, as a molding material for automobile parts, electrical products, building materials, packaging materials, and the like.

Examples of the present invention will be shown below to explain the present invention in more detail.

Example 1 Powdered crystalline ethylene propylene block copolymer (ethylene content -6% by weight, MF I -
0.35g/10m1n) to 100 parts by weight, 2-
3 parts by weight of hydroxy ethyl methacrylate, 1.5 parts by weight of t-butyl peroxy benzoate, and Irganox 1010 as an antioxidant.
1010) 0.1 part by weight and BHT0.1j! After adding 0.02 parts by weight of calcium stearate and mixing uniformly with a Henschel mixer, melt-kneading was performed using a single-screw extruder (NVC2 resin temperature -210°C manufactured by Nakayo Kikai) to obtain graft modification. Ethylene, propylene,
A block copolymer pellet (hereinafter referred to as MPP-1: resin composition of the present invention) was obtained.

The amount of graft modification of this MPP-1 was 1.1% by weight, and the MFI was 50 g/10 m1n.

Further, regarding this MPP-1, various physical properties shown in the item column of Table 1 below were measured according to the 457M method.

In addition, for comparison, ethylene content -6% by weight and M F
The physical properties of an ethylene-propylene block copolymer (hereinafter referred to as PP-1) with I = 50 g/10 m1n were similarly measured. The results are summarized in Table 1 below.As is clear from the results shown in Table 1 below, MPP-1 had almost no difference from PP-1 in terms of physical properties.

Table 1 ifl) Otsukwell R-Ske-J and the above MPP-1
(Resin composition of the present invention) and the above PP-1 (comparative material)
The moldability, appearance and reception of the molded product, paintability, and adhesion were investigated as follows.

-s Nono MPP-1 and PP-1 were used to injection mold a molded article with a length of 3.50 mm x width of 120 m x thickness of 3 m, respectively. There was no difference between MPP-1 and PP-1 in the moldability and appearance of the obtained molded products at this time, and both were good. Furthermore, the reception performance of these molded products was compared using a pencil and a 100-yen coin, but there was no significant difference between the two.

Planet P is applied to the surface of molded products with coating ratio MPP-1 and PP-1.
P-2 (manufactured by Origin Denki ■, wave-shaped paint) was adjusted to 14 seconds using a Ford cup (#4), and then applied to a film thickness of 16 μm using a spray gun. Drying was performed at 80°C for 30 minutes.

Paintability was evaluated by making 100 base lines on the coating film using a multi-cross cutter and performing a peel test using cellophane tape. The results were as follows.

(Results) In the case of the MPP-1 layer molded product (product of the present invention), the base grains did not peel off at all and the paintability was good, whereas in the case of the PP-1 layer molded product (comparison product) , 10 out of 100 base marks peeled off, resulting in poor paintability.

1) Using MPP-1 and PP-1, thickness 3.2mm x width 2
A 5 mm sheet was prepared and used for the test. The adherend is 0.8 arm thick x 25 m wide turtle ABS.
A manufactured sheet was used. In addition, as the adhesive, the main ingredient is ■Urethane adhesive G-806 modified (manufactured by Cemedine),
(2) A synthetic rubber adhesive G-250 (Cemedine type) and Dismodur R (manufactured by Sumitomo Bayer Urethane) were used as a curing agent. The following bonding method was used to bond the MPP-1 sheet and the ABS sheet, and the PP-1 sheet and the ABS sheet. Furthermore, the adhesiveness of these sheets was measured by the adhesive strength measuring method described below.

The results are shown below.

(Adhesion method) When using urethane adhesive, mix the main agent and hardening agent to 100%
If using a synthetic rubber adhesive, mix the main agent and curing agent in a ratio of 100:3 using a spray gun.
Approximately 1 each for the PP-1 sheet and the PP-1 sheet
After applying an amount of 50 g/nf, an ABS sheet was attached to each.

(Adhesive strength measurement method) MPP with ABS sheet attached using the above adhesive method
-I! After leaving the receipt sheet made of PP-1 for one week, 1
An 80° peel test is performed at a temperature of 80°C. The tensile test speed during peeling was 20 cm/min.

(Results) The 180° peel strength of the MPP-made sheet (product of the present invention) was
8.4kg/2.5c when using urethane adhesive
++1, 5.6 kg/when using synthetic rubber adhesive
2.5 cm, and cohesive failure of the adhesive occurred in both cases. On the other hand, the 180° peel strength of the PP-1 sheet (comparative amount) was O kg/2.5 cm for both adhesives.

Example 2 Crystalline ethylene-propylene block copolymer in pellet form (ethylene content = 8% by weight, MF I-0
,8g/10m1n) 100! 1 part by weight, 5 parts by weight of 2-hydroxy ethyl methacrylate, 2.5 parts by weight of t-butyl peroxy benzoate, and Irganox 1010 as an antioxidant.
1010) Add 0.1 part by weight and 1 part by weight of BHTO, and further add 0.02 part by weight of calcium stearate, mix uniformly in a tumbler, and then transfer to a two-stage twin-screw extruder (Kobe Steel Fault 2FCM). , resin temperature -220° C.) to obtain graft-modified ethylene-propylene block copolymer pellets (hereinafter referred to as MPP-2: resin composition of the present invention).

The amount of graft modification of this MPP-2 was 1.9N%, and the MFI was 40g/10mln.

Moreover, the physical properties of this MPP-2 were almost the same as those of an ethylene-propylene block copolymer with an ethylene content of 8% by weight and an MFI-40 g/10 ml.

Moreover, when this MPP-2 was examined for paintability and adhesiveness in the same manner as in Example 1, the following results were obtained.

(Results) Paintability: The base grains did not peel off at all, and the paintability was good.

Adhesion: 180" peel strength is 8.4 kg/2.5 cm when using urethane adhesive and 5.9 kg/2.5 c+w when using synthetic rubber adhesive. Cohesive failure of the adhesive also occurred.

Comparative Example 1 Ethylene graft-modified in the same manner as in Example 1 except that 0.3 parts by weight of 2-hydroxy ethyl methacrylate and 0.15 parts by weight of t-butyl peroxy benzoate were used. - Propylene-butt7-copolymer pellets (hereinafter referred to as MPP-3) were obtained.

The amount of graft modification of this MPP-3 was 0.06% by weight.

When this MPP-3 was examined for adhesiveness in the same manner as in Example 1, the following results were obtained.

(Results) The 180° peel strength was 0.3 kg/2.5 cm when using a urethane adhesive and 1.2 kg/2.5 cm when using a synthetic rubber adhesive. In this case, interfacial failure occurred between the MPP-3 sheet and the adhesive, and the adhesive strength was insufficient.

〔Effect of the invention〕

The polyolefin resin composition of the present invention retains the mechanical and thermal properties, specific gravity, surface scratch resistance, appearance, etc. of polyolefin, and has excellent adhesiveness and paintability.

Claims (2)

[Claims] (1) 100 parts by weight of polyolefin is added to the following general formula (I
) A polyolefin resin composition with excellent adhesiveness and paintability, obtained by melt-kneading a mixture containing 0.5 to 7 parts by weight of the compound represented by the following formula in the presence of an organic peroxide. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the above formula, R is a hydrogen atom or a methyl group, and n is 1 to 22.) (2) The polyolefin resin composition according to claim (1), wherein the polyolefin is crystalline polypropylene.