JPS6162544A - Resin composition - Google Patents

Abstract

PURPOSE:A composition that is composed of a specifically modified polypro pylene, a hydrocarbon elastomer or low-crystallinity ethylene-alpha-olefin copolymer and high-pressure, low-density polyethylene, thus showing good forming pro cessability and high adhesion to metal surfaces. CONSTITUTION:The objective composition is obtained from (A) 40-70wt% of a modified polypropylene containing 0.05-5wt% of an unsaturated carboxylic acid and/or an unsaturated carboxylic anhydride, preferably maleic anhydride or a mixture thereof with polypropylene, (B) 20-45wt% of a hydrocarbon elastomer such as ethylene-propylene copolymer or an ethylen-alpha-olefin copolymer of less than 30% crystallinity and (C) 5-30wt% of high-pressure, low-density polyethylenel, thus showing a melt flow index of 5-30. The (modified) poly propylene is a random copolymer containing 2-10wt% of ethylene component.

Description

[Detailed description of the invention] [Industrial field of application] Regarding the Fi resin composition of the present invention, it has particularly excellent moldability,
The present invention also relates to a resin composition that has excellent adhesive strength and adhesive durability with metal surfaces.

[Conventional technology]

Forming a laminate with metal materials by extrusion lamination of polyethylene, polypropylene, etc. has been conventionally practiced. In the case of metal and polypropylene laminates, various developments have been attempted, such as as a surface protection layer that takes advantage of its corrosion resistance, and as a lightweight composite material with a sandwich structure. Suggestions have been made. For example, JP-A-53-
trtrtt publication describes a method for manufacturing a laminate using an adhesive film made of a composition of a polyolefin grafted with unsaturated carboxylic acids and a hydrocarbon elastomer, and JP-A No. 2003-132113 The publication describes a laminate with metal using a composition consisting of modified polypropylene and an ethylene polymer.

[Problem that the invention seeks to solve]

There are two methods for laminating these resin compositions on metal: a method in which a resin film or sheet is made in advance, and then heated and pressurized using a press, roll, etc., and a method in which a film, sheet, or sheet extruded in a molten state is directly laminated. There is a way to do it. The latter case is more suitable for continuous production and more economical, but there are many problems such as stability during molding and uneven film thickness.

Particularly in recent years, there has been a demand for resins that are compatible with high-speed production, and their characteristics include good moldability and adhesive performance (
In particular, resins with a good balance of adhesive strength and adhesive durability are required.

Resin compositions that meet these requirements are difficult to obtain; some have excellent moldability but have poor adhesive strength, and others have poor adhesion strength. Although it has excellent IF strength, it has drawbacks such as poor workability. For example, the composition described in JP-A-53-rrrrμ has excellent adhesive strength, but tends to cause uneven film thickness and film breakage during extrusion lamination.

[Ninth way to solve the problem]

As a result of various studies in order to overcome the above-mentioned drawbacks and obtain a resin that has excellent properties and a good overall balance of various performances, the present inventors have found that a desirable resin composition can be obtained by combining specific resins in a specific ratio. Discovering that things can be obtained,
The present invention has been achieved.

That is, the present invention provides (a) a mixture of polypropylene and modified polypropylene or 0 to 70% by weight of modified polypropylene containing 0.05 to 7% by weight of unsaturated carboxylic acid and/or unsaturated carboxylic anhydride based on the total weight; (hereinafter referred to as "component (a)")
(b) Hydrocarbon elastomer or low-crystalline ethylene-α olefin copolymer with crystallinity of less than 3° 20-4L j X j-% (hereinafter "0) component"
), and <C) high-pressure low-density polyethylene (hereinafter referred to as r (c
) s-Jo type weight component.

The present invention will be explained in detail below.

The polypropylene used in the present invention usually contains 2 to 30% ethylene, considering that if the ethylene content is too low, the adhesive strength and adhesive durability will be poor, and if the ethylene content is too high, the heat resistance will decrease too much due to softening. A propylene-ethylene random copolymer containing 70% (hereinafter, "ch" indicates "wt%" unless otherwise specified) is used. Although a small amount of comonomer other than ethylene can be included, it is not desirable to use an amount that drastically changes the properties of the polypropylene copolymer, and it is preferable that the amount of ethylene monomer is small.

The molecular weight of polypropylene is usually 0.1-10. It is preferably about 1 to /Q. Particularly preferred are modified polypropylenes or mixtures of modified polypropylenes having a melt index of j to 30 after the modification described below.

Unsaturated carboxylic acids and their anhydrides include acrylic acid,
Maleic acid, fumaric acid, maleic anhydride, endo-bicyclo-[co, 2. l]-5-heptene-2,3-dicarboxylic acid anhydride, and the like. Among these, maleic anhydride is preferred. Moreover, mixtures of these can also be used.

As a method for producing modified polypropylene, which is component (a), a graft reaction can be carried out by bringing polypropylene, a fermentation monomer, and a radical generator such as an organic peroxide into contact with each other by various methods. Melt mixing method,
Solution Grafting Method, Slurry Craft Method Although various grafting methods have been proposed, any method is possible, and the melt grafting method is particularly desirable because it is economical. In this case, the graft reaction can be easily carried out by kneading polypropylene and an acid monomer such as maleic anhydride in the presence of an organic peroxide at a temperature of about 1♂Q to 260°C. The 'Jt of the unsaturated carboxylic acid to be grafted is 0.01-j% based on the weight of the modified polypropylene or the mixture of modified polypropylene and polypropylene. Graph) Conditions in which l exceeds j% are unfavorable because discoloration, polymer deterioration, etc. tend to occur.

Hydrocarbon-based di-stomers include α-olefins such as ethylene and propylene, in-olefins such as in-butylene, and di-olefins such as butadiene and imprene. "ymhe, *"°7
``$% / °O1s J'e *1 A typical example of a nidistomer obtained by
Ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-propylene-diene copolymer (K
PDU), polyisobutylene, etc.

These nidistomers require moderate miscibility when mixed with polypropylene, so Mooney viscosity of 100
Below! It is desirable to have at least a certain degree. Mooney viscosity! Below that, the contribution to adhesive strength is small.

It was. Low-crystalline ethylene-α-olefin copolymer is a partially crystalline copolymer with fewer copolymer monomers than the above-mentioned ethylene-α-olefin copolymer, and has a crystallinity of less than 30%, preferably 20%.
% or less and a density of 037 to 01 is desirable. For example, 9 copolymers can be obtained by polymerizing in a molar ratio of ethylene P≠~10 mole and butene/l-4~coj mole-0. This stiff copolymer exhibits properties intermediate between elastomers and crystalline polyethylene.

As component (b), this copolymer and/or the above-mentioned hydrocarbon-based didistomer are used.

The high-pressure low-density polyethylene of component (c) is polyethylene polymerized under high pressure using a radical initiator. The polymer has a density Q, io, o, terj.

Melt index 0. j to 30 is desirable. %
It is desirable to use a lami grade with a melt index of 1 to 3 and a relatively high melt tension.

Mixing of the three components (a) and (b) and (c) may be carried out using a blender such as a melt extruder or a blender under normal polyolefin mixing conditions.Also, the order of blending may be arbitrary, and the λ It is possible to mix the components in advance or to mix the three components all at once.

Also, the mixing ratio of each component (a), (b), and (c) is (a
) Component 4AO to 70% (b) Component KoO≠jChi (c) Component 5 to 30%, and preferably the melt flow index of the composition after mixing is j%3Q.

Special K It is necessary to select the (1+) component and (c) component while considering the balance between formability and required adhesive strength. 0) It is best to use a blend that increases the amount of the ingredients. In any case, the amount of each component must be within the above range; if component (b) is less than 20%, adhesive strength, especially secondary adhesion such as salt water resistance, will not be sufficient; μ! If it is above -, the heat resistance and hardness of the component itself will be inferior, which is not desirable. (c) What are the ingredients? If it is less than 3Q, it is undesirable because the effect of improving molding processability, especially a stable lamination film, cannot be obtained, and if it is more than 3Q, it is not preferable because the adhesive force decreases.

In addition, it is preferable that component (a) is contained in a proportion of 10% or more in the entire composition, and if it is less than 11 as described above, the composition has a good balance of adhesive strength, durability, and heat resistance. This is undesirable because it also leads to a decrease in adhesiveness when laminated with a polypropylene layer as an adhesive layer.

In addition to the above three components (-), (b), and (c), the present composition may also contain stability rules, pigments, various fillers, etc., and the content thereof may be adjusted as long as it is compatible with the purpose of the present invention. There are no restrictions.

〔Effect of the invention〕

As described above, since the present invention contains a specific resin in a specific ratio, it is possible to provide a resin composition with a good balance of moldability and adhesiveness. It is excellent in terms of quality.

The present invention will be described in more detail below with reference to Examples.

〔Example〕

Raw material resin> (a) Polypropylene a-/: Propylene-ethylene copolymer, ethylene Kanakura 7% Melt flow index 01l a-+2: Propylene homopolymer, ethylene content Q% Melt flow index o, r b-/: Ethylene-glo Pyre/copolymer, propylene content /r molten melt index /, j density o, r r.

b-2: Ethylene-butene copolymer, butene content /
J Molch Melt Index ≠, O Density o, ry.

(c) High-pressure process low-density polyethylene ethylene homopolymer melt index Modification of polypropylene > a-/IOO weight part of polymer anhydrous maleic MO,
J Heavy Part, α, α′ Vistasha Butyl Peroxy 7
Paradiisoglobilpe/zeno and orx were mixed and melted and kneaded at 4°C using an extruder equipped with an inner diameter of 4tOrrtxφ, L/D=-Hiro, and a full-flight type screw. The resulting modified polypropylene A/7 was extracted with acetone to remove unreacted monomers, and the amount of grafting was determined using an infrared method. lJt of maleic anhydride was grafted. Melt flow index (2
30°C) ii3o.

The homopolymer of a-1 was also treated in the same way to make it anhydrous! Reic acid graft Q, 72 heavy weight loss, melt flow index 2
A modified polypropylene a'-1 of No. 5 was obtained.

Preparation of resin composition> The above modified polypropylene a'-/, 2 and (b), (c
) with each polymer at 23Q℃ using an ≠owrtφ extruder.
The resin compositions shown in Table 1 were prepared by kneading them.

<Evaluation of adhesive strength and adhesive durability> ftO, 2ran thick aluminum f with chromate treatment
Prepare a YM board (HT board) and a polypropylene homopolymer sheet (PP sheet) with a thickness of 100μ, and place the above resin composition film on the At board (thickness: 200μ)/
P P sheet/above resin composition film (thickness λooμ
) A laminate of LHT plates was heated and compressed using a press to form a mold.

Table 1 shows the evaluation results for each resin composition.

The peel strength in Table 1 was measured by cutting out a short width test piece with a width λ of 544 cm (/inch) from the above laminate and measuring it using a Tensilon tensile tester to evaluate the adhesive strength. Salt water resistance is an evaluation of adhesive durability by immersing the above test piece in warm water at -20°C and peeling it off after 1,000 hours, with no change in the adhesive surface at all. ◎, those that have undergone erosion of 0”-211111 or less are X for those that are more than Osxtrm.
It is displayed as .

Evaluation of formability> A T-die (width 200 mesh,
Dailip 0.7 tone, coat hanger type) Yoshiko 7
A film of the above resin composition was extruded at 0°C and an extrusion rate of /ky/hr, and a film of chill roll (200trvt, L The ratio of the film width is expressed as the neck-in ratio.The selvage thickness ratio is also expressed as an index of the selvage height by measuring the average thickness at the center of the film and the thickness at both ends (selvages) of the film. It is something that

The larger the neck-in ratio (the closer to l)
Moreover, the smaller the edge thickness ratio, the better the moldability, and the more uniform the thickness and width of the film can be formed.

Procedural amendment September 2nd, 1982 2. Name of launch resin composition 3 Person making the amendment

Claims (4)

[Claims] (1) (a) A mixture of polypropylene and modified polypropylene or 40 to 70% by weight of modified polypropylene containing 0.05 to 1% by weight of unsaturated carboxylic acid and/or unsaturated carboxylic acid anhydride based on the total weight (b) A resin composition comprising 20-45% by weight of a hydrocarbon elastomer or a low-crystalline ethylene-α-olefin copolymer with a crystallinity of less than 30%, and (c) 5-30% by weight of high-pressure low-density polyethylene. . (2) The resin composition according to claim 1, wherein the polypropylene and/or modified polypropylene is a random copolymer containing 2 to 10% by weight of an ethylene component. (3) The resin composition according to claim 1 or 2, wherein the unsaturated carboxylic anhydride is maleic anhydride. (4) The resin composition according to any one of claims 1 to 3, which has a melt flow index in the range of 5 to 30.