JPS61258857A - Modified polyethylene composition - Google Patents

Abstract

PURPOSE:A composition having a high production rate, comprising a modified polyethylene and a modified polyisobutylene, capable of carrying out coating in improved adhesiveness even at reduced preheated temperature of a material to be coated, not releasing a coated layer caused by softening, etc., in the case of multi-layer coating. CONSTITUTION:(A) 50-95wt% modified polyethylene obtained by reacting a linear low-density polyethylene having 7-50g/10min melt index with an unsaturated carboxylic acid or its derivative is blended with (B) 5-50wt% polyisobutylene and/or modified polyisobutylene obtained by reacting the polyisobutylene with an unsaturated carboxylic acid or its derivative. A polyisobutylene having 10-150 Mooney viscosity and <=30% crystallinity is preferable as the component B.

Description

[Detailed description of the invention] Industrial applications FIELD OF THE INVENTION The present invention relates to modified bolietele/complex acids.

Conventional technology Conventionally, the inner and outer surfaces of metal pipes, metal plates, electric wire cables, steel wires, etc., have been covered with polyethylene to improve corrosion resistance, appearance, food hygiene, etc., or the disadvantages of various synthetic resins. Composites made by bonding with polyethylene are known to improve this. The polyethylene used in this case is known to be modified polyethylene or a composition thereof, which is obtained by modifying polyethylene with an unsaturated carboxylic acid or a derivative thereof to impart adhesiveness in order to improve the adhesiveness with metals and various synthetic resins. There is.

For example, a composition consisting of a hydrocarbon synthetic rubber and a modified ethylene polymer that is substantially a medium-low pressure ethylene polymer having a specific melt index ratio grafted with an unsaturated carboxylic acid or a derivative thereof (JP-A-56-120750) (No. Publication), polyethylene modified with an unsaturated carboxylic acid or its anhydride to which a specific ethylene/α-olefin random copolymer has been added is heat-bonded to a metal body that has been coated with an epoxy resin adhesive and heat-treated. Method (Unexamined Japanese Patent Publication No. 1983-
168628), a method in which a single layer of thermosetting Evoquin resin braimer is formed on the metal surface, modified polyethylene with a melt index of 3 t/1o min or less is fused to the surface, and polyethylene is fused to the surface ( JP-A-59-150575) and the like have been proposed.

On the other hand, in order to improve the adhesion between metals and thermoplastic resins and polyethylene and their durability, compositions of polyethylene and synthetic rubber, in which specific linear low-density polyethylene is modified with unsaturated carboxylic acids or derivatives thereof ( JP-A-57-165413) and a composition obtained by reacting a mixture of specific linear low-density polyethylene and synthetic rubber with an unsaturated carboxylic acid or a derivative thereof to modify the composition (JP-A-57-165469). Proposed.

Problems to be Solved by the Invention Although the composition and method proposed above improve the adhesive strength between polyethylene and adherends such as metals and thermoplastic resins, the adhesion at low preheating temperatures of the adherends is poor. There wasn't enough about sex. That is, unless the modified polyethylene or its composition is wetted onto an adherend at a temperature equal to or higher than the melting point of the resin, sufficient adhesiveness will not be exhibited. Therefore,
Usually, the adherend is preheated to near the melting temperature of the resin, and its surface is coated with the molten resin.

However, when coating a metal body multiple times, for example when coating the inner and outer surfaces of a steel pipe, if the steel pipe whose inner surface is coated first is preheated to near the melting point of the resin, the already coated surface will soften and become damaged. In order to avoid peeling and peeling, a resin was needed that could be bonded even if the preheating temperature of the steel pipe was lowered considerably. Furthermore, if the preheating temperature of the adherend cannot be lowered, the cooling rate after plugging is slowed down to coat the adherend, which causes a problem in that the line speed (production speed) decreases.

The purpose of the present invention is to solve the above-mentioned problems and provide a modified polyethylene composition that has excellent adhesive properties even when the preheating temperature of the adherend is lowered compared to conventional compositions. shall be.

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above problems, and as a result, have developed a specific range of melt index (hereinafter referred to as M
The inventors have completed the present invention by discovering that a composition containing a modified linear low-density polyethylene and polyisobutylene and/or modified polyisobutylene achieves the object of the present invention.

That is, the present invention provides (1) (A) MF~502/1
Modified polyethylene 50 made by reacting unsaturated carboxylic acid/acid or its derivative with linear low density polyethylene of 0 min.
~95% by weight, and 03) a modified polyethylene composition comprising 5 to 50 parts of a modified polyimbutylene obtained by reacting polyisobutylene and/or the polyimbutylene with an unsaturated carboxylic acid or a derivative thereof. .

Linear low density polyethylene (hereinafter referred to as L) used in the present invention
LDPm) can be prepared using ethylene and α-olefins, e.g., t-haftene-1, pentene-1, hexene-1, It is produced by copolymerizing with 4-methylpentene-1, heptene-1, octene-1, etc., and the M process is 7 to 50 g/10 minutes, preferably 8 to 20 r/10 minutes. It is. Here, the α-olefin is generally contained in an amount of 3 to 20 weight units.

Among these LLDPIs, the density when polymerized by low pressure gas phase method is 1905 to 0.950 t/♂, and the weight average molecular fW
/ number average molecular weight Mn of 3 to 12 is desirable. If the M process of the above LLDPF is less than 7 g/10 minutes, the adhesion at a low preheating temperature of the adherend is insufficient;
If it exceeds or7'lo, the strength of the resin will be insufficient. Furthermore, polyethylenes other than linear low-density polyethylene do not have sufficient adhesion to the adherend and their durability.

Commercially available polyisobutylene can be used as the polyisobutylene used in the present invention, but Mooney viscosity (ML1+4.100℃, JI
SK-6300 or less] is 10 to 15°, and crystallinity (X-ray diffraction method) is preferably 50% or less. Also,
Synthetic rubbers other than polyisobutylene do not have sufficient adhesion to adherends.

Examples of the unsaturated carboxylic acids used in the present invention include acrylic acid, methacrylic acid, maleic acid, fumaric acid, itaconic acid, ntraconic acid, endo-bicyclo[2,2
,1]-1,4゜5, 6,7.7-hexachloro-5
-hebutene-2,3-dicarboxylic acid, endo-bean claw [2,2,1]-5-hebutene-2,3-dicarboxylic acid, kudzu-4-fuclohexene-1゜2-dicarboxylic acid, etc. can give. In addition, examples of derivatives of unsaturated carboxylic acids include acid anhydrides and esters, such as maleic anhydride, citraconic anhydride, endo-pycyclo[2
,2゜1]-1,4,5,6,7,7-hexachloro-
5-hebutene-2,3mm dicarboxylic acid endo-bean claw [2,2,1]-5-heptene-2,3-dicarboxylic anhydride, cis-4-cyclohexene-1,2-m
Hydrodicarboxylic acid, methyl acrylate, methyl methacrylate, ethyl acrylate, ethyl methacrylate, butyl acrylate, butyl methacrylate, maleate ester (
Monoester, diester) l: 6 digits.

Various known methods can be used to react LLDPF: or polyimbutylene with an unsaturated carboxylic acid or a derivative thereof. For example, I, LDPFX or polyisobutylene and an unsaturated carboxylic acid or its derivative in the presence or absence of a solvent as an organic peroxide reaction initiator, e.g.
Ditert-butyl peroxide, dicumyl peroxide, benzoyl peroxide, bar hexa2.
5-benzoyl, 2,5-dimethyl-2゜5-di(ternarybutylberroquine)-hex''7-3 etc.
The mixture is mixed in advance using a mixer such as L, Henschel mixer, ribbon blender, etc., and this mixture is melt-kneaded using a Banbury Mixer 1 single-screw or multi-screw extruder at a temperature above the melting point of polyethylene or polyisobutylene and below 280°C.

Alternatively, LLDPE or polyisobutylene may be dissolved in a solvent, and an unsaturated carboxylic acid or its derivative and a reaction initiator may be added to the solution to cause the reaction.

Here, the tray of unsaturated carboxylic acid or its derivative added to LLDPB or polyisobutylene is Q, 01 to 3 weight %
is preferred. Therefore, the addition of unsaturated carboxylic acids or derivatives thereof and organic peroxide initiators it
l, DP1! ! or unsaturated carboxylic acid or derivative thereof [IL05-5
i1 Ut parts, and reaction initiator CL001 to 0.5 parts by weight are preferred.

In addition, the content of unsaturated carboxylic acid or its derivative in the modified polyethylene or modified polyimbutylene obtained is 0.
．． If the amount is less than 1% by weight, the strong adhesive force of the present invention cannot be obtained, while if it exceeds 3% by weight, no increase in adhesive force is observed, and the generation of gel-like substances and discoloration increase, resulting in economical problems. is also disadvantageous.

Next, the modified polyethylene composition of the present invention contains 50 to 95% by weight of modified polyethylene, preferably 60 to 85% by weight of #'i, and 5 to 50% by weight of polyethylene and/or modified polyisobutylene, preferably 15 to 40% by weight. 'j! :
It consists of %. If the amount of modified polyethylene is less than 50-31% by weight and the amount of polyisobutylene and/or modified polyisobutylene is less than 5 parts by weight, the object of the present invention cannot be achieved. Some of the above modified polyethylenes include unmodified polyethylene,
For example LLDPK or 1. LDPK may be replaced with a mixture of low-density polyethylene, medium-density polyethylene, or high-density polyethylene. In this case, the modified polyethylene needs to weigh 10% by weight, and the unmodified polyethylene needs to weigh 85% by weight or less, preferably 25 to 60% by weight.
Make it regrettable. However, modified polyimbutylene is
It may be partially or completely modified, or it may be a modified mixture of LLDPE and polyimbutylene.

The composition of the present invention can be produced by mixing modified LLDPE, polyimbutylene and/or modified polyimbutylene, VC, and unmodified polyethylene in the above-mentioned mixing ratio. Is each of the above ingredients equal? In order to obtain a composition that has phytophilic properties, for example, the mixture is premixed using a Hennel mixer, a ribbon blender, etc., and this mixture is mixed using a Banbury mixer, roll, extruder, etc. from a temperature above the melting point of the composition. A method of melting and kneading at a temperature of 280° C. or lower is desirable. In addition, when the polyisobutylene is in the form of a veil, it is desirable to heat and melt-knead it using a Banbury mixer, rolls, or the like.

Further, the composition of the present invention may be one in which a mixture of LLDPI and polyimbutylene in the above-mentioned mixing ratio is reacted with an unsaturated carboxylic acid or a derivative thereof. Furthermore, unmodified polyethylene and/or unmodified polyimbutylene may be mixed into this modified mixture at the above-mentioned mixing ratio.

The compositions of the present invention contain various additives, such as heat stabilizers,
Ultraviolet absorbers, nucleating agents, antistatic agents, coloring agents, and various fillers such as inorganic fillers and plasticizers can be blended. These additives and the like may be mixed during or after the preparation of the composition.

The modified polyethylene composition of the present invention can then be formed into a suitable laminate with a metal or thermoplastic resin.

The metals used in the laminate using the modified polyethylene composition of the present invention include iron, aluminum, copper, zinc, nickel, tin, stainless steel, brass, tinplate, galvanized iron, etc. in the form of plates, foils, cylinders, and tubes. , lines, or other shapes. Examples of thermoplastic resins include polyamides such as nylon 6, nylon 66, nylon 11, nylon 12, and nylon 6-10; polyolefins such as olefin homopolymers such as polyethylene, polypropylene, and polybutene, or copolymers thereof; Partially converted polyvinyl alcohol into 7-cetalized resin (vinylon),
Examples include resins obtained by partially hydrolyzing ethylene-vinyl acetate copolymer (Ehar), polyesters such as polyethylene terephthalate and polybutylene terephthalate, and polyvinyl chloride, with nylon and vinylon being particularly preferred.

A laminate using the modified polyethylene composition of the present invention can be obtained by laminating the modified polyethylene composition of the present invention and one selected from the above metals or thermoplastic resins.

The method of obtaining the laminate is not particularly limited, and examples include a method of forming each into a film or sheet and then thermocompression bonding, a method of laminating outside the die, a method of laminating (coextrusion) inside the goo, a method of forming the laminate in the form of a tube or 7. - Known methods such as extrusion coating or powder coating can be used. In addition, when laminating with metal, pre-treatments such as solvent degreasing, pickling, shot blasting, zinc phosphate treatment, calcium phosphate, etc. are usually performed, and furthermore, by using an epoxy resin primer as a primer treatment, A laminate with stronger adhesive strength can be obtained. As the epoxy resin primer, a one-component or two-component modified epoxy resin primer is preferred from the viewpoint of heat resistance or stability.

The structure of the laminate using the modified polyethylene composition of the present invention is basically a two-layer structure in which the modified polyethylene composition of the present invention is laminated with a material selected from the metals or thermoplastic resins described above, but as necessary. Various combinations can be made.

For example, modified polyethylene composition (hereinafter referred to as iron composition)/metal, the composition/thermoplastic resin, the composition/metal/the composition, metal/the composite acid/metal, metal/the composite acid/thermal In combinations of plastic resins, thermoplastic resins/the composite acid/thermoplastic resins, etc., these can be further combined, or they can be combined with other materials such as fibers, paper, woodblocks, etc.

The composition of the present invention forms a suitable composite (coating, lamination, etc.) with metal or thermoplastic resin as described above, and is particularly useful for coating metal pipes. An example of manufacturing will be explained.

The base metal tube is cleaned by surface treatment such as shot blasting, grid blasting, or pickling. Furthermore, it is desirable to apply an Epoquine adhesive or the like as a brimer treatment thereon in order to obtain a resin layer with stronger adhesive strength.

The pretreated metal tube is heated to a desired temperature, for example, 100°C or higher, preferably 110 to 15°C, by high-frequency induction heating or the like.
The composition is heated to 0°C and applied to the outer surface of the metal tube at a temperature above the melting point.
Preferably, it is coated by extruding it into a tube or winding it into a sheet at a temperature of 200 to 230°C. The thickness of the coating varies depending on the purpose, but is usually about α3w. Furthermore, an exterior material such as polyolefin/, preferably high-density polyethylene is applied thereon to a melting point higher than the melting point, preferably 2oo to 230%.
The product is extruded into a tube or rolled into a sheet at a temperature of °C and immediately cooled with water after coating. The thickness of the exterior material is usually about 2 mm. Note that the covering of the exterior material may be omitted as appropriate depending on the application.

In addition, when the above-mentioned metal tube coating is applied to both the inner and outer surfaces of the metal tube, the pretreated metal tube is heated to 100 to 150°C, and the composition and polyolefin, preferably polyethylene, are coated on the inner surface in that order. Paint is applied to form a resin layer.

Next, this inner-coated metal tube is heated to a temperature of 1 aac to less than the melting point of the inner-coated resin, and the outer surface of this metal tube is coated with the composition and polyolefin in the same manner as described above.

Since the composition of the present invention exhibits adhesive properties at a lower preheating temperature (such as for metal pipes) than conventional modified polyethylene compositions, it can be used to coat both the inner and outer surfaces of metal pipes as described above. It is possible to make a difference in preheating temperature, and there is no problem caused by softening or melting of the previously coated resin layer (inner surface). In addition, conventionally, when the preheating temperature cannot be lowered, the coating is performed by slowing down the cooling rate of the coated metal tube, but the composition of the present invention does not require this, and the line speed (production rate) can be reduced. It will not deteriorate.

Effects of the Invention Compared to already proposed modified polyethylene compositions, the composition of the present invention can heat adherends such as metals and thermoplastic resins from a much lower preheating temperature to a higher temperature. Shows excellent adhesion. Therefore, in multilayer resin coating, there is no inconvenience caused by softening or melting of the already coated layer, and there is no need to slow down the cooling rate after coating, so there is no reduction in production rate.

The composition of the present invention has the above-mentioned excellent properties,
Suitable for composites with metals and thermoplastic resins, especially multilayer composites. Examples of composites include the inner and outer surfaces of steel pipes and cast iron pipes, steel plates, metal foils, electric wire cables, coatings of steel wires, tank linings, and multilayer films with various thermoplastic resins, sheets, bottles, containers, etc. Examples include laminates.

EXAMPLES Next, the present invention will be explained in detail with reference to examples. In addition,
All parts and marks in the examples are based on weight, and the test method is as follows.

(1) M engineering A8TM D-1238K (190℃, 2160t)
(2) Peel strength (4) In the case of steel plate After electrolytically degreasing a pickled steel plate (SS-AL) 1OOX 100×α31fl, preheat it to a predetermined temperature on a heating plate, and apply the composition of the present invention on top of it. Sheet (
A test piece was prepared by heating a sheet of high-density polyethylene (thickness 1 inch)/high density polyethylene (thickness 3 inch) to 220° C., melting and fusion bonding, allowing it to stand for 10 seconds, and cooling it by immersing it in running water. The resin layer of the test piece was cut into a width of 10 mm and a portion was peeled off to provide a gripping margin.
Peeling speed 50 wa 7 using Instron tensile testing machine
The 90° peel strength in minutes was measured at 23°C and 60°C.

(B) In the case of nylon, a nylon-6 sheet with a thickness of 11 is preheated to a predetermined temperature on a heating plate, and a sheet of the composition with a thickness of 111 II is heated to 220° C. to melt and fuse. After 10 seconds, it was placed on a cooling plate and cooled to prepare a test piece. The resin layer of the test piece was cut to a width of 25 m, a portion was peeled off to provide a gripping margin, and the 90° peel strength was measured at 23° C. at a speed of 50 m for 7 minutes using an Instron tensile tester.

Examples 1 to 3, Comparative Examples 1 and 2 LLnpx with different MI (comonomer-butene-1)
1.2 parts of maleic anhydride and 2,5-dimethyl-2,5-di(teributylperoquine) to 100 parts
1025 parts of hexyl/-3 were blended and mixed in a Henschel mixer, and the mixture was fed to a 65 wmφ-screw extruder and melt-kneaded at 230° C. and 6 Orpm to obtain maleic anhydride-modified LLDPI. This modified LLDPK and polyimbutylene [manufactured by Etsuno Kagaku Co., Ltd., Vistanecs MML-8]
0 (product name)] in the proportions shown in Table 1 and heated at 230°C.
The mixture was heated, melted and kneaded to obtain a composition.

Using each of the obtained compositions, a laminate with steel plates of each preheating temperature was created and the 90° peel strength was measured, and the results are shown in the table.
Shown in 1.

For comparison, when LLDPI of 5j710 minutes was used and poly(inbutylene was substituted) ethylene butene rubber [
Mitsui Petrochemical Co. g, A-4085 (product name), EBR]
In the case of using , a composition was prepared and a laminate was prepared in the same manner as in Example 1, and the 90° peel strength was measured, and the results are also listed in Table 1.

Poor-1 Examples 4 to 9, Comparative Examples 3 to 6 In Examples 1 to 3, the blending amount of maleic anhydride was 0.
Modified LLDPB was obtained in the same manner except that the amount was changed to 6 parts. This modified LLDP111i, polyisobutylene, and unmodified LLDPI were blended in the proportions shown in Table 2, mixed in advance in the same manner as in Example 1, and then heated and melt-kneaded at 230° C. using an extruder to obtain a composition. A laminate with a steel plate and nylon-6 was prepared using the obtained composition, and the 90° peel strength was measured, and the results are shown in Table 2.

For comparison, MI is 1P/10 minutes and 5? Preparation and lamination of the composition in the same manner as in Example 4 also when using I/10 minutes LDPK and when using low density polyethylene (11,Di) or high density polyethylene (HDPK) instead of LLDPE. A product was prepared and its 90° peel strength was measured, and the results are also listed in Table 2.

Example 11.12 After mixing unmodified LLDPI and polyimbutylene (from P) used in Examples 1 and 2 in the proportions shown in Table 3, maleic anhydride was added to this mixture in the same manner as in Example 1. A modified polyethylene composition was obtained by the reaction. A laminate with a steel plate was prepared using the obtained composition, and the 90° peel strength was measured, and the results are shown in Table 3.

Example 13.14 After mixing the unmodified LLDPI and polyimbutylene (from P) used in Examples 1 and 2 in the proportions shown in Table 3, a maleic anhydride-modified polyethylene composition was prepared in the same manner as in Example 11. I got it.

This modified polyethylene and unmodified LLDPE were blended in the proportions shown in Table 3, mixed in advance, and then heated at 230°C using an extruder.
The composition was obtained by heating, melting, and kneading. A steel plate and a laminate were prepared using the obtained composition, and the 90° peel strength was measured, and the results are also listed in Table 3.

Table 3 Example 15, Comparative Example 8 A 50wφ8GF black tube was descaled by pickling treatment as a test metal tube, and then heated to each temperature shown in Table 4 by high frequency induction heating. The modified polyethylene composition used in Example 11 was extruded and coated into a tube at a resin temperature of 220° C. with a thickness of 1 m and a line speed of 1 WIZ using a 651a Iφ extruder, and cooled in a water tank with a distance of s from the die. A resin-coated steel pipe was obtained. The 90° peel strength of the coated steel pipe obtained was measured and the results are shown in Table 4.

For comparison, a modified polyethylene composition prepared by reacting a mixture of LiLDPK of 59/10 minutes with polyimbutylene with maleic anhydride in the same manner as in Example 1 was used, but a modified polyethylene composition was used in the same manner as in Example 12. A resin-coated steel pipe was obtained.

The 90° peel strength of the obtained coated steel pipe was measured and the results are also listed in Table 4.

Table-4

Claims (1)

[Claims] (1) (A) Modified polyethylene 50-9 made by reacting linear low-density polyethylene with a melt index of 7-50 g/10 min with an unsaturated carboxylic acid or its derivative
5% by weight, and (B) 5 to 50% by weight of polyisobutylene and/or a modified polyisobutylene obtained by reacting the polyisobutylene with an unsaturated carboxylic acid or a derivative thereof.
A modified polyethylene composition consisting of.