JPH0812818A - Adhesive resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject composition suitable for coating cables, metal plates and inner and outer faces of metal pipes useful at a low temperature, having excellent adhesiveness to metals and low-temperature impact resistance by blending a mixture of a prescribed PE and copolymerized rubber with a specific modified PE. CONSTITUTION:This composition is obtained by blending (A) 100 pts.wt. of a mixture of 20-70wt.% of a middle- or high-density polyethylene and 80-30wt.% of ethylene-propylene copolymerized rubber with (B) 10-100 pts.wt. of a modified PE obtained by grafting 10-100 pts.wt. of an unsaturated dicarboxylic acid such as maleic acid or itaconic acid to a linear low-density PE. The middle- or high-density PE in the component A is preferably a PE having <=3g/10 minutes melt index, >=0.94g/cm<3> density and >=10 molecular weight distribution (weight-average molecular weight/number-average molecular weight).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive polyethylene composition having excellent adhesiveness to metals and polyolefins, and particularly excellent impact resistance at low temperatures.

[0002]

2. Description of the Related Art Conventionally, in order to improve the corrosion resistance, appearance, and food hygiene of metals, the inner and outer surfaces of metal pipes (for example, steel pipes), metal plates, electric wires, cables, etc. have been changed to polyethylene, polypropylene, etc. It is known to laminate (adhere) a modified polyolefin grafted with unsaturated dicarboxylic acids.

However, conventional modified polyolefins have the drawbacks of low adhesion strength to metals such as steel, iron, and aluminum, and insufficient impact resistance at low temperatures. It has a drawback that it cannot be used in the field where the property is required.

[0004]

An object of the present invention is to provide an adhesive polyethylene composition which has a large adhesive strength with a metal and is excellent in low temperature impact resistance. In particular, when coating steel pipes for the purpose of anticorrosion, it has excellent impact resistance at extremely low temperatures (-60 ° C or less) and new adhesiveness with excellent adhesive performance at relatively high temperatures (40 ° C or more). To provide polyethylene.

[0005]

[Means for Solving the Problems] First, the present invention relates to a linear low content for 100 parts by weight of a mixture consisting of 20 to 70% by weight of medium and high density polyethylene and 80 to 30% by weight of ethylene-propylene copolymer rubber. The present invention relates to an adhesive polyethylene composition containing 10 to 100 parts by weight of modified polyethylene obtained by grafting unsaturated dicarboxylic acids on high density polyethylene.

Secondly, a medium high density polyethylene having a melt index of 3 g / 10 minutes or less, a density of 0.94 g / cm ³ or more, and a weight average molecular weight / number average molecular weight of 10 or more, 20 to 70% by weight of ethylene-propylene copolymer. An adhesive polyethylene composition characterized by containing 10 to 100 parts by weight of modified polyethylene obtained by grafting unsaturated dicarboxylic acids on linear low-density polyethylene to 100 parts by weight of a mixture consisting of 80 to 30% by weight of polymerized rubber. Regarding

The medium and high density polyethylene which is one of the compounding components of the adhesive polyethylene composition of the present invention is Philips obtained by polymerizing ethylene and alumina or a catalyst such as chromium oxide supported on silica-alumina. Standard polyethylene, standard method polyethylene obtained by polymerizing using a catalyst such as molybdenum oxide supported on alumina, polyethylene obtained by polymerizing using a Ziegler type catalyst composed of a transition metal compound and an organometallic compound, and the like. To be

Among them, polyethylene obtained by polymerizing by a bimodal method, which is a method of producing and mixing in a plurality of polymerization vessels using a Ziegler type catalyst, can be preferably used.

As the medium and high density polyethylene, those having the following physical properties are particularly preferable. The melt index at 190 ° C is 3 g / 10 minutes or less, more preferably 2 to 0.
It is 1g / 10 minutes. Density is at 0.94 g / cm ³ or more, more preferably 0.945~0.960g / cm ^3. Weight average molecular weight / number average molecular weight is 10 or more, more preferably 12
~ 25.

The ethylene-propylene copolymer rubber which is one of the compounding components of the adhesive polyethylene composition of the present invention is
Particularly, those having the following physical properties are preferable. Melt flow rate at 230 ° C is 1.0g / 10 minutes or less. The propylene content is 20 to 40% by weight, more preferably 25 to 35% by weight.

The modified polyethylene which is one of the blending components of the adhesive polyethylene composition of the present invention is a linear low density polyethylene grafted with unsaturated dicarboxylic acids.

The linear low density polyethylene is a known method such as solution polymerization, gas phase polymerization or slurry polymerization of ethylene and α-olefin in the presence of a Ziegler type or chromium type catalyst under medium and low pressure. It is an ethylene-α-olefin copolymer having a relatively low density, which has been copolymerized with.

Examples of the comonomer for copolymerization include α-olefins having 3 or more carbon atoms such as propylene, butene-1, pentene-1, 4-methylpentene-1, and octene-1. The repeating unit derived from the α-olefin of the linear low density polyethylene is preferably 0.1 to 10 mole%.

As the linear low density polyethylene, those having the following physical properties are particularly preferable. The melt index at 190 ° C. is 0.1 to 10 g / 10 minutes or less, more preferably 0.5 to 5 g / 10 minutes.

Examples of the unsaturated dicarboxylic acids include unsaturated dicarboxylic acids such as maleic acid, itaconic acid and citraconic acid, and anhydrides of these acids.

The amount of unsaturated dicarboxylic acids to be grafted on the linear low density polyethylene is preferably 0.1 to 5% by weight, more preferably 0.5 to 2% by weight.

As a method for grafting the unsaturated dicarboxylic acid to the linear low density polyethylene, for example, the linear low density polyethylene and the unsaturated dicarboxylic acid can be produced by melt-kneading in the presence of a reaction initiator.

As the reaction initiator, an organic peroxide type reaction initiator such as t-butyl-hydroperoxide can be used. Also, cumene dimers such as 2,3-dimethyl-2,3-diphenylbutane and their derivatives can be used.

The blending ratio of each of the above components of the adhesive polyethylene composition of the present invention is 20 to 70% by weight of medium and high density polyethylene, preferably 30 to 60% by weight, 80 to 30% by weight of ethylene-propylene copolymer rubber, Preferably, 70-40% by weight,
10 to 100 parts by weight, preferably 30 to 70 parts by weight of modified polyethylene obtained by grafting unsaturated dicarboxylic acids onto linear low-density polyethylene based on 100 parts by weight of the mixture. The adhesive polyethylene composition of the present invention further improves the adhesiveness and low temperature characteristics by containing the respective components in the above proportions.

The adhesive polyethylene composition of the present invention comprises an antioxidant, an ultraviolet absorber, a flame retardant, an inorganic
Organic fillers, pigments, antistatic agents, etc. can be added.

The adhesive polyethylene composition of the present invention can be formed into a film or sheet by a method similar to ordinary polyethylene, such as extrusion molding. It can be used alone or as a laminated metal plate (foil) or a covering tube by being laminated with a metal plate, foil or tube. Also, it can be used as a laminate having a sandwich structure in which metal plates are laminated on both sides of the adhesive polyethylene composition, or a laminate having a structure in which a polyolefin (for example, polyethylene) is further laminated to an adhesive polyethylene composition laminated with a metal. You can

The laminate of the adhesive polyethylene composition of the present invention and a metal is formed by a method of thermocompression bonding a film or sheet of the adhesive polyethylene composition with a metal, a method of laminating outside the die, and a method of laminating inside the die. , Extrusion coating, powder coating, and the like.

Examples of the metal used include iron, aluminum, copper, zinc, nickel, tin and stainless steel. Particularly, a steel plate and a TSF steel plate are preferable. Before the metal is laminated with the adhesive polyethylene composition, a known pretreatment, for example, solvent degreasing, pickling, shotplast, or the like pretreatment is performed, and further by a primer of an epoxy resin as a primer treatment, A laminate having a high adhesive strength is obtained.

[0024]

The adhesive polyethylene composition of the present invention is
Since it has a large adhesive strength with a metal and exhibits excellent low temperature impact resistance, it can be suitably used for coating cables, metal plates and inner and outer surfaces of metal pipes used at extremely low temperatures.

[0025]

【Example】

(A) Low temperature impact test (1) Preparation of low temperature impact test piece Shot blasted steel plate (SS-41: 100 mm x 150 mm x 9 m
Immerse m (t) in acetone and sonicate for 30 minutes to degrease it. After air-drying, put it in an open at 140 ° C for 30
Hold for more than a minute, then place on a hot plate heated to 180 ℃,
Two-part curing type epoxy resin (bisphenol A type epoxy resin (epoxy equivalent 190) 100 parts by weight and amine curing agent
50 parts by weight) and apply with a bar coder.
Prepare to a thickness of μm and cure for 30 seconds. Next, T
Die-molded sheet of adhesive polyethylene composition (100
mm × 150mm × 0.2mm (t)), and cure for 1 minute,
Then, melt index (MI) 0.1g / 10min high pressure method low density polyethylene T die forming sheet (100mm × 150mm
× 2.5mm (t)), polyester film (Mylar), 1
The above shot blast steel sheets preheated to 60 ° C are laminated in this order, a weight of 10.kg is placed on the steel sheets and crimped for 3 minutes, then put in water, cooled and used as a test piece for low temperature impact test. did.

(2) Low temperature impact test The test piece of (1) above was put in a low temperature tank kept at -60 ° C with dry ice / ethanol, and after 30 minutes or more, the low density polyethylene layer of the test piece was placed on top. Install horizontally. At this time, adjust the amount of ethanol so that there is 10 mm or more ethanol from the top of the test piece. Place a steel punch with a tip of R = 19mmφ on the test piece, 4kg
The weight is freely dropped from a predetermined height (the distance from the bottom of the weight to the upper part of the punch) and collided with the upper part of the punch.
Take out the test piece and inspect it for penetration and cracks (test 10 times and indicate the presence or absence of penetration and cracks).

(B) Adhesive strength test (1) Preparation of test piece for measuring adhesive strength A sheet of an adhesive polyethylene composition (1) formed by T-die molding
00mm × 150mm × 0.2mm (t)) is laminated in the same manner as A- (1), and then the adhesive polyethylene composition sheet and the high-pressure low density polyethylene sheet (100mm × 150mm × 2.
5mm (t)) to form a partially unbonded part, stack Mylar in the lengthwise direction from the tip to the part 50mm, and then apply the high-pressure low-density polyethylene sheet as in A- (1). By laminating, a test piece for measuring adhesive strength is prepared.

(2) Measurement of adhesive strength The test pieces prepared in B- (1) were cracked at intervals of 10 mm in a long direction with a cutter knife, and unbonded using a tensile strength tester equipped with a thermostatic chamber. The polyethylene layer of the part was sandwiched between chucks and mounted on a jig for 90 ° peeling, and after the test piece was sufficiently heated to 40 ° C, a 90 ° peeling test was performed at a peeling speed of 50 mm to measure the adhesive strength.

Example 1 50% by weight of high-density polyethylene having a melt index (MI) of 1.7 g / 10 minutes, a density of 0.949 g / cm ³ , a weight average molecular weight / number average molecular weight of 18 produced using a Ziegler type catalyst
Melt flow rate at 230 ° C: 0.7 g / 10 minutes, 100 parts by weight of a mixture of 50% by weight of ethylene-propylene copolymer rubber having a propylene content of 27% by weight, melt index (MI) of 2.0 g / 10 minutes, density 1.0% by weight of maleic anhydride in vapor phase linear low density polyethylene (LLDPE) produced using a Ziegler-based catalyst with 0.919 g / cm ³ , weight average molecular weight / number average molecular weight 4, butene-1 content 8% by weight And 0.25% by weight of 2,3-dimethyl-2,3-diphenylbutane as a radical generator are mixed in a Henschel mixer and melt-kneaded in a twin-screw extruder at 260 ° C under a nitrogen stream. .
95% by weight maleic anhydride graft-polymerized modified product 30
Parts by weight were mixed and melt-kneaded with a twin-screw extruder to produce an adhesive polyethylene composition.

This adhesive polyethylene composition was molded into a sheet having a width of 150 mm and a thickness of 0.2 mm by using a T-die molding machine and subjected to a low temperature impact test (A) and an adhesive strength test at 40 ° C. (B). It was subjected to measurement. In the low temperature impact test, the test was performed 10 times at an energy of 5 kg · m. The low-density polyethylene layer penetrated and no crack occurred. The 90 ° peel adhesive strength test at 40 ° C was 16 kg / cm 2.

Example 2 Except that the blending ratios of high-density polyethylene and ethylene-propylene copolymer were changed to 60% by weight and 40% by weight, respectively.
The same procedure as in Example 1 was performed. 5 kg / m in low temperature impact test
The test was performed 10 times with the energy of. The low-density polyethylene layer penetrated and no crack occurred. The 90 ° peel adhesive strength test at 40 ° C was 16 kg / cm 2.

Comparative Example 1 Example 1 was used as a blending component of the adhesive polyethylene composition.
30% by weight of modified polyethylene graft-polymerized with maleic anhydride and melt index (MI) 1.0 g / 10
Example 1 was repeated except that only 70% by weight of vapor phase linear low density polyethylene (LLDPE) produced by using a Ziegler catalyst was used. 5Kg in low temperature impact test
・ Tests were performed 10 times with m energy. The low-density polyethylene layer penetrated, and the low-density polyethylene layer was cracked 6 times. The 90 ° peel adhesive strength test at 40 ° C was 17 kg / cm 2.

Comparative Example 2 Example 1 was used as a blending component of the adhesive polyethylene composition.
Example 1 except that only 30% by weight of the modified polyethylene graft-polymerized with maleic anhydride used in Example 1 and 70% by weight of the ethylene-propylene copolymer rubber used in Example 1 were used.
I went the same way. In the low temperature impact test, the test was performed 10 times at an energy of 5 kg · m. The low-density polyethylene layer penetrated and no crack occurred. The 90 ° peel adhesive strength test at 40 ° C was 2 kg / cm 2.

Claims (2)

[Claims] 1. A modified polyethylene obtained by grafting an unsaturated dicarboxylic acid on linear low density polyethylene to 100 parts by weight of a mixture consisting of 20 to 70% by weight of medium and high density polyethylene and 80 to 30% by weight of ethylene-propylene copolymer rubber. Ten
An adhesive polyethylene composition, characterized in that it contains from 100 to 100 parts by weight. 2. The adhesive property according to claim 1, wherein the medium-high density polyethylene has a melt index of 3 g / 10 minutes or less, a density of 0.94 g / cm ³ or more, and a weight average molecular weight / number average molecular weight of 10 or more. Polyethylene composition.