JPS58151215A - Fomation of formed body of polyolefin or polyolefin copolymer coated on surface with ultra-high-molecular- weight polyethylene formed member - Google Patents

Abstract

PURPOSE:To obtain the titled formed body excellent in molding workability, heat resistance, dimentional stability, creep free properties, etc., by a method wherein ultra-high-molecular-weight PE molded member and polyolefin molded member coincident therewith in shape are molded under a specified condition, and both molded members are strongly jointed. CONSTITUTION:When the surface of a molded body of polyolefin or polyolefin copolymer (for example; polyethylene or ethylene and propylene copolymer, etc.) is coated with ultra-high-molecular-weight polyethylene, ultra-high-molecular- weight polyethylene molded member and polyolefin or polyolefin copolymer molding so as to coincide therewith in shape are molded at a temperature of not less than the crystalline melting point of ultra-high-molecular-weight polyethylene and not more than 300 deg.C under a pressure of 50-500kg/cm<2>, and the aimed coated molded product strongly jointing both members may be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for coating the surface of a molded article of polyolefin or polyolefin copolymer with ultra-high molecular weight polyethylene, so that the polyolefin or polyolefin copolymer and the ultra-high molecular weight polyethylene are firmly bonded at the boundary. The present invention relates to a method for molding an integrally molded product, which is characterized by having a joint that is rigid.

Ultra-high molecular weight polyethylene has the highest abrasion resistance of all plastics, and also has excellent physical properties such as low coefficient of friction, low-temperature impact resistance, and sound deadening properties, making it suitable for use in bar shooter linings, conveyors, etc. , screws, pickers, etc.

However, even though ultra-high molecular weight polyethylene has a high melting temperature, polymer chains break at high temperatures or under mechanical stress, resulting in a decrease in molecular weight. be damaged.

Therefore, during molding, it is necessary to avoid applying high temperatures or mechanical stress as much as possible.

For example, in compression molding, to mold a 30W+ sheet, sifting must be performed at a relatively low temperature of 200°C to 220°C for 3 hours and for a long time.
In addition, extrusion molding requires the use of a special extrusion molding machine, and the extrusion speed is extremely low, which is a major disadvantage in the molding process.

Therefore, the conventional method requires a long cycle for molding.
The molding cost is high, and since only one type of ultra-high molecular weight polyethylene is used, the heat resistance, dimensional stability, and creep resistance of the molded product are poor.

Furthermore, because molding is difficult, they are formed into simple shapes, often sheets or rods, so in order to obtain molded objects with complex shapes, cutting must be used, and molded objects with free shapes can be obtained. It is extremely difficult to obtain it economically.

Attempts to improve moldability by focusing on the abrasion resistance, low coefficient of friction, low-temperature impact resistance, sound-deadening properties, etc. possessed by ultra-high molecular weight polyethylene have already been published in Japanese Patent Publication No. 43-24525 and Japanese Patent Publication No. 44-27463. This is done by mixing large amounts of plasticizers, lubricants, etc.

However, in general, mixing large amounts of plasticizers, lubricants, etc. in order to improve molding processability can certainly improve molding processability, but it can significantly reduce physical properties, especially wear resistance. Tend.

Conventionally, joining ultra-high molecular weight polyethylene and polymer molded articles was difficult because the surface of ultra-high molecular weight polyethylene was inert.
It was considered extremely difficult.

In order to improve the above-mentioned drawbacks, the present inventors investigated the bondability of many polymers with ultra-high molecular weight polyethylene and found that only polyolefins or polyolefin copolymers exhibited strong bonding strength. .

That is, a polyolefin or polyolefin molded to match the shape of an ultra-high molecular weight polyethylene body and a polyolefin or polyolefin copolymer powder, granule, or pellet, or a mixture thereof, or an ultra-high molecular weight polyethylene molded body. By heating and pressurizing the copolymer molded product at a temperature higher than the crystal melting point of the ultra-high molecular weight polyethylene, the ultra-high molecular weight polyethylene and the polyolefin or polyolefin copolymer form a strong bond at the interface in a very short time. The present inventors have discovered that there is a bond, and have carried out the present invention.

Furthermore, they have found that the method of the present invention improves moldability, heat resistance, dimensional stability, creep resistance, flexibility, cushioning properties, etc., and has completed the present invention.

In the present invention, the following molding method can be used.

1. A pre-formed ultra-high molecular weight polyethylene and a polyolefin or polyolefin copolymer molded body formed to match the ultra-high molecular weight polyethylene are heated at a temperature above the crystal melting point of the ultra-high molecular weight polyethylene and below 300°C, preferably 1
50℃ or higher and 250℃ or lower (7) Temperature, s krd or higher 5
00 kg/cd! The following is preferable (7 or 20 on acceptance inspection)
By compression molding under a pressure of 50 kVcI/ or less, the ultra-high molecular weight polyethylene and the polyolefin or polyolefin copolymer have a strong bond at the boundary, and a polyolefin or a polyolefin whose surface is coated with ultra-high molecular weight polyethylene is formed. This is a method for molding a molded article of a polyolefin copolymer.

2. A pre-formed ultra-high molecular weight polyethylene molded body and polyolefin or polyolefin copolymer powder, granules, pellets, or a mixture thereof are heated to a temperature higher than the crystalline melting point of the ultra-high molecular weight polyethylene by 300°C.
℃ or less, preferably 150℃ or more and 250℃ or less,
5kVcl/ to 5 million M or less, preferably 20
Compression molding may be performed under a pressure of Vcr 1 to 250, or injection molding or extrusion molding may be performed using a preformed ultra-high molecular weight polyethylene molded body as an insert.

Here, if the bonding temperature is below the crystal melting point of ultra-high molecular weight polyethylene, sufficient bonding force will not be obtained;
If the temperature exceeds .degree. C., the molecular weight of the ultra-high molecular weight polyethylene decreases due to thermal decomposition and 1-1 physical properties deteriorate, which is not preferable.

If the bonding pressure is less than 5'%'7, the time required for molding will be significantly longer, and the bonding force will be weaker than 5oOkV.
If it is crI or more, the time required for molding does not change, which is not preferable.

The ultra-high molecular weight polyethylene used in the present invention refers to a composition containing as a main component a polyethylene having a viscosity average molecular weight of 500,000 or more, preferably 1,000,000 or more.

Additives to ultra-high molecular weight polyethylene include aliphatic hydrocarbons such as paraffin wax and low molecular weight polyethylene wax, alicyclic hydrocarbons such as cyclopentene and cyclopentadiene, cetyl alcohol, stearyl alcohol, etc. (7) Higher There are plasticizers, lubricants, surfactants, etc. such as aliphatic esters such as flucol and butyl oleate, and higher fatty acid metal salts such as zinc stearate, and these may be contained singly or in combinations of two or more. Also preferably used in the present invention.

As the polymer referred to in the present invention, high, medium or low density polyethylene, polypropylene, polybutene, polybutadiene, polyinoprene, etc. can be used. In addition, polyvinyl acetate, ethylene-propylene copolymer, ethylene-
It refers to polyolefins such as propylene-diene copolymers and ethylene-vinyl acetate copolymers, or polyolefin copolymers, and two or more of these polymers can also be used. .

In addition, these polyolefins or polyolefin copolymers are coated with glass fibers, carbon fibers,
Those containing fillers such as calcium carbonate, silica powder, alumina, and aluminum hydroxide, or additives such as plasticizers, stabilizers, lubricants, vulcanizing agents, colorants, and antistatic agents can also be preferably used.

Polymers other than those mentioned above include, for example, chlorinated resins such as polyvinyl chloride, polyvinylidene chloride, chlorinated polypropylene, or copolymers thereof, nylon 4, nylon 6, nylon 11, nylon 12, nylon 6, nylon 6, nylon Homoamides or copolyamides such as 6 and 10, saturated polyesters such as polyethylene terephthalate, polybutylene terephthalate, etc., copolymers such as polyacronitrile, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, etc. , polyacetal, polycarbonate, polymethyl methacrylate, etc., as in Examples and Comparative Examples, are not bonded at all or are bonded only weakly, and only polyolefins or polyolefin copolymers are bonded strongly by the seven methods of the present invention. It can have a bond.

The ultra-high molecular weight polyethylene molded product as used in the present invention refers to any shape such as a film, sheet, plate, cylinder, hollow, square prism, etc., and is mainly thin-walled.
Part or all may be thick-walled.

In the present invention, the molded product of polyolefin or polyolefin copolymer means that in order to obtain a molded product with the desired wall thickness and shape, the molding cycle is shortened, and the molded product has excellent heat resistance, dimensional stability, creep resistance, and flexibility. A retaining material of ultra-high molecular weight polyethylene for improving properties, buffering properties, etc.,
It can be of any shape, such as a sheet, plate, cylinder, cylinder, sphere, hollow, square prism, etc., but it usually has a joint surface that is similar to or corresponds to the joint surface of the ultra-high molecular weight polyethylene to be joined. Preferably.

In the present invention, strong bonding means that ultra-high molecular weight polyethylene and polyolefin or polyolefin copolymer are
The condition is that the bonded surface has sufficient peel resistance strength and that the bonded surface does not peel off in practice.

In the present invention, a molded article of polyolefin or polyolefin copolymer whose surface is coated with ultra-high molecular weight polyethylene means a molded article of polyolefin or polyolefin copolymer whose surface is coated with ultra-high molecular weight polyethylene. This refers to a molded product in which the parts that require impact resistance and sound deadening properties are covered with ultra-high molecular weight t-polyethylene.

Normally, to obtain a molded body using ultra-high molecular weight polyethylene alone,
Although sintering is required for a long time, according to the present invention, the wall thickness of ultra-high molecular weight polyethylene can be reduced, so the molding cycle can be significantly shortened, and therefore molding costs can be reduced. .

Furthermore, the advantage of the present invention is that the amount of expensive ultra-high molecular weight polyethylene used can be significantly reduced.Also, since the polyolefin or polyolefin copolymer can be selected according to the purpose, it has excellent heat resistance, dimensional stability, and creep resistance. Physical properties such as elasticity, flexibility, and cushioning properties can also be improved.

Furthermore, conventionally, molded objects with complex shapes could be obtained by cutting, but in the present invention, since ultra-high molecular weight polyethylene is used in a relatively thin wall, molding processability is improved, and molded objects with complex shapes can also be obtained. It can be efficiently molded in one piece.

The present invention will be specifically explained below using Examples and Comparative Examples.

Example 1 A high-density polyethylene sheet (25W x 45 x 3 tml) previously molded under normal molding conditions was placed in a compression mold, and an ultra-high molecular weight polyethylene sheet (25W x 45 x 3 tml) previously molded under normal molding conditions was placed on top of it. 25WX45
) x 2t 11ml), heated under pressure using Japanese cypress to raise the temperature to 180°C, and then heated to 180°C.
Keep at 80°C, 50kg//cI& for 5 minutes.

After that, cooling was started and the temperature was raised to 50° C. in 10 minutes.

A high-density polyethylene sheet coated with ultra-high molecular weight polyethylene was obtained by the above method.

Table 1 shows the results of the beating abrasion test, tensile test, and heat cycle test of the obtained sheet.

The method for each test is as follows.

(1) Beating abrasion test An iron rod (diameter 2) weighing 5 kg was allowed to fall naturally onto the center of the sheet 100 times from a height of 7 cm, and the condition of the sheet at that time was observed.

(2) Tensile test During the above sheet forming process, aluminum foil of 25W x 3o%: 0.1 was placed between both sheets as shown in Figure 1, and the resulting sheet was pulled in the thickness direction. The bonding force between them was determined.

(3) Heat cycle test The obtained sheet was subjected to one cycle of -40°C x 30 minutes + 80°C x 30 minutes, and the state of the sheet after 5 cycles was observed.

Examples 2 to 9 Except for molding with the polymer and heating temperature shown in Table-1,
Each sheet was obtained in the same manner as in Example 1.

The test results of the obtained sheet are shown in Table-1.

Example 10 High-density polyethylene 3.31 was placed in a compression mold, and an ultra-high molecular weight polyethylene sheet (25W x 45J x 2t
) and heated under bag pressure to 50℃ to raise the temperature to 180℃, then continue to heat at 180℃, 50kVcr/
1 for 5 minutes.

Cooling was then immediately started and brought to 50° C. in 10 minutes.

A sheet of high density polyethylene coated with ultra high molecular weight polyethylene was obtained in the above manner.

The test results of the obtained sheet are shown in Table-1.

Examples 11 and 12 Except for molding with the polymer and heating temperature shown in Table 1,
Each sheet was obtained in the same manner as in Example 10.

Table 1 shows the test results for the notebooks obtained.

Comparative Examples 1 to 9 Except for molding using the polymer and heating temperature shown in Table 1,
Each sheet was obtained in the same manner as in Example 1.

The test results of the obtained sheet are shown in Table-1.

Comparative Examples 10 to 12 Except for molding with the polymer and heating temperature shown in Table-1,
Each sheet was obtained in the same manner as in Example 10.

The test results of the obtained sheet are shown in Table-1.

Table-1 Note 2 The test results in Table 1 have the following meanings.

(1) Appearance: Good - No peeling immediately after taking out from the mold.

(2) Tapping abrasion test: Good - no peeling after the test.

(3) Heat cycle test: Good - no peeling after the test.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a test piece used in a tensile test, FIG. 2 is a plan view thereof, and FIG. 3 is a side view thereof. In these figures, (a)--Aluminum foil (25WX45JxO, 1tm
)(b)...Ultra high molecular weight polyethylene layer (c)...
Polymer layer arrow indicates direction of pull. Patent Applicant Asahi Yokuzai Kogyo Co., Ltd. Procedural Amendment (hri Showa Tough s>, r + r 2r u ↑, 'I' +, 'l- Office Director Shima Gyukata's revision) 1,
° 1 list fl display ``PT Tomo I Zan Tahu 3 ri z71 Relationship with 11 items Chakushi Biosemu name (name) M 椹 oh 1 工 9 ト 口 4, representative
People i7tswl (fj'RJ% rhgLp'fi L
w゛Mnkiζaftv>7, Contents of amendment 1, "Polybutene" on page 8, lines 15-16 of the present specification is corrected to "polybutene." 2. In the same book, page 8, lines 16-17, [ etc. can be used. Also, delete the j. 3. On page 8, lines 17-20 of the same book, “Polyvinyl acetate ~
"Voriolephy/Copolymer" should be corrected as follows. "Polyolefins such as polyvinyl acetate, polyolefin copolymers such as ethylene-propylene copolymers, ethylene-propylene-diene copolymers, and ethylene-vinyl acetate copolymers" 4, page 11, line 11 of the same book: Correct the phrase "covered" to "covered." 5. Delete "by pressure" on page 12, line 19 of the same book. 6. The scope of claims of this application is amended as shown in the attached sheet. Claim (1): In order to coat the surface of a molded product of polyone fins or polyolefin copolymer with ultra-high molecular weight polyethylene, molding is performed to match the shape of the molded product of ultra-high molecular weight polyethylene. By molding the molded polyolefin or polyolefin copolymer at a temperature below the crystal melting point of ultra-high molecular weight polyethylene and below 300°C under a pressure of 5 to 500 to 1. ,
A method for molding a molded article of polyolefin or clay olefin copolymer whose surface is coated with ultra-high molecular weight polyethylene, characterized in that a strong bond is formed between the two. (2) In order to coat the surface of the molded product of polyolefin or polyolefin copolymer with ultra-high molecular weight polyethylene, the molded product of ultra-high molecular weight polyethylene and powder, granule, or pellets of polyolefin or polyolefin copolymer or The mixture thereof is heated at a temperature higher than the crystal melting point of ultra-high molecular weight polyethylene and lower than 300°C, 5
Molding of polyolefin or polyolefin copolymer whose surface is coated with ultra-high molecular weight polyethylene, characterized in that a strong bond is maintained between the two by molding under a pressure of at least 500 kI/d7. How to shape your body. (3) The polyolefin or polyolefin copolymer is a polyolefin such as high, medium or low density polyethylene, polypropylene, polybutene, polybutadiene, polyisoprene, polyvinyl acetate, ethylene-propylene copolymer, ethylene-propylene-diene, etc. polymer,
Claim 1, which is a polyolefin copolymer such as ethylene-vinyl acetate copolymer or a mixture thereof
The molding method described in item 1 or 2.

Claims (3)

[Claims] (1) In order to coat the surface of the polyolefin or polyolefin copolymer molded product with ultra-high molecular weight polyethylene, the ultra-high molecular weight polyethylene molded product and the polyolefin or polyolefin copolymer molded to match the shape thereof The combined molded body was heated at a temperature of not less than the crystal melting point of ultra-high molecular weight polyethylene and not more than 300°C, 5 kl/, 1
A method for molding a polyolefin or polyolefin copolymer molded product whose surface is coated with ultra-high molecular weight polyethylene, characterized in that the molding is performed under a pressure of at least 500 kVcrI or less to form a strong bond between the two. . (2) In order to coat the surface of the polyolefin or polyolefin copolymer molded product with ultra-high molecular weight polyethylene, the ultra-high molecular weight polyethylene molded product and polyolefin or polyolefin copolymer powder, granule, or pellet or their The mixture is heated at a temperature above the crystal melting point of ultra-high molecular weight polyethylene and below 300°C,
A polyolefin or polyolefin copolymer whose surface is coated with ultra-high molecular weight polyethylene, which is characterized in that it maintains a strong bond between the two by molding kg//cr/ under a pressure of at least 500 kFm. A method of forming a molded body. (3) Polyolefin polymers include polyolefin copolymers such as high, medium, or low density polyethylene, polypropylene, polybutene, polybutadiene, polyisoprene, polyvinyl acetate, etc., ethylene-propylene copolymers, ethylene-propylene copolymers, etc. diene copolymer,
Claim 1, which is a polyolefin copolymer such as ethylene-vinyl acetate copolymer or a mixture thereof
The molding method described in item 1 or 2.