JPS59179574A - Covering tape or sheet - Google Patents

Abstract

PURPOSE:A covering tape, having a specific unvulcanized acrylic elastomer layer on one side of a synthetic rubber sheet, etc. and a rubber based pressure-sensitive adhesive layer on the other side thereof, improved weather resistance and heat resistance, and useful for protection and color identification of exposed piping materials, etc. without forming water channels. CONSTITUTION:A covering tape or sheet obtained by forming an acrylic elastomer layer containing a graft copolymer prepared by addition polymerization of an ethylenically unsaturated monomer, preferably 2-butyl methacrylate or acrylic acid, capable of giving homopolymer or copolymer thereof having >=300 deg.K glass transition temperature in an amount to give preferably 20-60wt% ethylenically unsaturated monomer in the total amount of the monomer and an acrylic polymer onto the acrylic polymer having viscoelasticity of about unvulcanized rubber, preferably 1-50kg/cm<2> elasticity in 0.05-2.00mm. thickness on one side of a synthetic rubber and/or natural rubber sheet or tape and a rubber based pressure-sensitive adhesive layer in 0.05-2.00mm. thickness on the other side thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a covering tape or sheet, and more specifically, a tape or sheet useful for protecting exposed structures such as exposed piping and exposed steel structures, and for color-coding L7. A coated tape or sheet is provided.

As a means of transporting fluids such as oil, gas, and water,
There is a method of using a buried pipeline, but since such a pipeline is made of metal, there is a problem that it corrodes in the mouth.

As a method of preventing pipeline corrosion, a method has been adopted in which the pipe surface is protected with bituminous material, but there is a problem in that the bituminous material layer is easily damaged by external impact.

In recent years, as a method to solve the problems of such methods, a method has been adopted in which the pipe surface is coated with plastics such as polyethylene or polyvinyl chloride, and the following three methods are generally known as such coating methods.

1) Method of heating the pipe and coating the surface with molten plastic via a layer of primer (-1 cooling method).

2) A method of processing plastics into a cylindrical heat-shrinkable tube in advance, attaching it to the pipe via a primer, heating the tube to shrink it, and covering it.

3) Process the glass into a tape or sheet shape and form an adhesive layer on one surface of the tape or sheet in advance, and apply this to the pipe surface in a sushi roll shape or with or without a primer layer. A method of covering by overlapping parts in a spiral shape.

M-pipes protected with plastic in this way have a remarkable effect as a buried pipeline in terms of corrosion protection and service life, compared to pipes protected with bituminous materials. However, the exposure pipeline did not necessarily have sufficient effects.

In particular, when the surface of an exposed pipeline is protected using method 3), there is no tightening of the tape or sheet due to soil pressure, unlike in the case of buried pipelines. When plastics are used, so-called water supply (mizumichi) is formed on the lamp part of the tape.
There was a problem that the corrosion resistance was significantly reduced.

On the other hand, when transmitting water, gas, electricity, etc. through exposed pipelines, it is legally required to clearly mark them with colors such as blue, green, or orange. However, exposed pipelines have the disadvantage that they are susceptible to discoloration when exposed directly to sunlight.

In order to prevent water leaks from forming, the inventors made a colored rubber tape using known combs such as synthetic rubber or natural rubber and wrapped it around an exposed water pipeline. There was no occurrence of welt itch that was seen with hard plastics. However, the disadvantages of rubber deterioration and discoloration being easily caused by sunlight could not be improved.

Therefore, we focused on the fact that acrylic rubber has good weather resistance,
Forming an acrylic rubber layer on the colored rubber tape,
When wrapped around an exposed water pipeline, the acrylic rubber layer developed fine cracks due to the tension caused by the wrapping.
Stress was concentrated on this, resulting in a large crack. The base IJ rubber portion exposed in the crack deteriorated due to sunlight.

In addition, when we conducted a similar test using unvulcanized acrylic rubber, no cracks like the one described above occurred, but since it is unvulcanized, acrylic rubber has poor heat resistance, so it may cause problems in summer, for example. In this case, when an external impact is applied to the tape, the acrylic rubber layer in that part becomes thin, and the base rubber in that part deteriorates [7. As a result of extensive research into a coated tape or sheet that has excellent four-weather resistance and heat resistance, and does not generate welts, we have formed a special unvulcanized acrylic elastic layer on a known rubber support. We found that the solution could be solved by
This led to the establishment of FJJ.

That is, the present invention applies a homopolymer or copolymer glass to an acrylic polymer having viscoelasticity comparable to unvulcanized rubber on one side of a synthetic rubber and/or natural rubber sheet or tape. An acrylic elastic layer containing a graft polymer obtained by addition polymerizing one or more cochilenic unsaturated monomers that can be the above is formed, and a rubber pressure-sensitive adhesive layer is provided on the other side. The invention relates to coating tapes or sheets that are primarily useful for protecting the surfaces of exposed structures.

The acrylic elastic layer formed on one side of the coated tape or sheet of the present invention is made of a specific acrylic polymer base, and a graft polymer obtained by addition-polymerizing a specific ethylenically unsaturated monomer thereto. Although this graft polymer is unvulcanized, it exhibits the same characteristics as a vulcanized one, and since it is based on an acrylic polymer, it has excellent weather resistance and heat resistance.

For this reason, by using a coated tape or sheet using a tape or sheet on which such an acrylic elastic layer is formed, it is possible to solve the problem of fading, which is a drawback of conventional coated tapes or sheets, and it can be used industrially. A very useful covering tape or sheet can be provided.

The acrylic polymer used in the present invention has viscoelasticity comparable to that of unvulcanized rubber, and its elastic modulus measured by the method described below is usually about 1 to 50 Kl/'crn2. The average molecule 1 (weight: 耶) is at least 3
10,000 or more, and a suitable VC is 10,000 or more and 1,000,000 or less.

In addition, the elastic modulus mentioned here means that when the polymer is molded into a sheet shape and the thickness is 0.5 am, I Omm x 50 a
Create a zanopulus of size m, and 2 for each zample.
0'CX 65%R,H, 20m between chucks
It was determined from the stress-strain curve when stretched at a speed of 7 minutes to m x 50 mm.

In order to obtain the above-mentioned acrylic polymer, generally one or more argyl esters of acrylic acid or methacrylic acid with an alcohol component having an average carbon number in the range of 13 to 12 are used as the main monomer, Usually, the above-mentioned main monomer and other copolymerizable vinyl monomers are used in combination, and these are mixed in an appropriate ratio, and generally the latter monomer is 5
If the polymerization is carried out within the range of 0% by weight or less by a method such as solution polymerization, emulsion polymerization, suspension polymerization, or bulk polymerization, using a chain transfer agent such as a mercaptan if necessary, to obtain a predetermined molecular vinegar. good.

Other vinyl monomers that can be copolymerized include styrene, acrylonitrile, vinyl acetate, vinyl chloride, vinyl propionate, mono- or diesters of maleic acid, acrylic acid, methacrylic acid, crotonic acid, maleic acid, and itacone. Acid, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl methacrylate, N-N-dimethylaminoethyl acrylate-1-, N-N-dimethylaminoethyl methacrylate, N-tert-butyl Examples include aminoethyl acrylate, bis(N-N-dimethylaminoethyl) maleate, acrylamide, ivy-acrylamide, N-methylolacrylamide, glycidyl acrylate, and the like.

In this invention, it is necessary to attach (graft polymerize) a specific ethylenically unsaturated monomer to the acrylic polymer having viscoelasticity comparable to that of the unvulcanized comb mentioned above. By using L, it is possible to obtain an acrylic elastic body having excellent elastic properties that can replace vulcanized rubber and conventionally known thermoplastic glass mer.

The ethylenically unsaturated monomer used for this purpose has a homopolymer or copolymer glass transition temperature of 30
If one or more monomers have a glass transition temperature of 0° or more, and the glass transition temperature is lower than 300°, good results will not be obtained in the elastic properties of the addition polymerized polymer. Furthermore, among the two or more ethylenically unsaturated stoichiomers whose copolymers can have a glass transition temperature of 300° or more, there are monomers whose homopolymers can each have a glass transition temperature of 300° or more. In addition to mixtures, monomers whose homopolymer glass transition temperature can be 300' or higher and homopolymers whose glass transition temperature is 300'
Mixtures with lower monomers are also included. In the latter case, the copolymer may have a glass transition temperature of 300° or higher depending on the composition ratio of the monomers.

Preferred examples of such ethylenically unsaturated monomers include, for example, 2-butyl methacrylate (318'
K), 3,3-dimethylbutyl methacrylate (318
°K), 3,3-dimethyl-2-butyl methacrylate (381'K), ethyl methacrylate (338 °K),
Glycidyl methacrylate (319°K), inbornyl methacrylate (383°K), inbutyl methacrylate (326'K), inbornyl acrylate (3
54°K), methyl methacrylate (378°K), ethyl methacrylate (378°K), n-furovir methacrylate (308°K), inbornyl acrylate (308°K),
367°K), styrene (389″K L 4-ter
t-Butylstyrene (403°K), 2,4-diimpropylstyrene (44+'K), 2,5-dimethylstyrene (416°K), 3,4-diethylstyrene (38
2°K), 2-hydroxymethylstyrene (43B'
K), 4-methylstyrene (366°K), 2-methylstyrene (366'K), and the like.

Still together with the monomers mentioned above, other monomers which can be copolymerized with these and whose glass transition temperature of the copolymer can be higher than 300°, such as acrylic acid (360°K), methacrylic acid (501°K), Ethyl acrylate (24
Also suitable are monomers such as methyl acrylate (279°K), butyl methacrylate (249°K), and 2-methoxyethyl methacrylate (290°K).

In this invention, the proportion of the ethylenically unsaturated monomer used as described above depends on the composition and molecular weight of the acrylic polymer used, the type of ethylenically unsaturated monomer, and whether the addition polymerization reaction is carried out in the presence of a solvent. There are considerable differences depending on whether the reaction is carried out in the presence or absence of a solvent, and if a solvent is used, the type of solvent used. However, in general, the amount may be generally 8 to 66% by weight, preferably about 20 to 60% by weight, based on the total amount with the acrylic polymer.

Addition polymerization reaction is carried out by solution polymerization method or bulk polymerization method.
The polymerization can be carried out according to a conventional method using an appropriate radical polymerization catalyst, and in some cases, it is also possible to initiate the polymerization by using energy such as light or electron beams.

As a radical polymerization catalyst, an azo compound such as azobisisobutyronitrile may be used, but particularly suitable J[
are benzoyl peroxide, cumene hydroperoxide, Lert-butyl peroxide, Le
It is preferable to use organic peroxides such as rl niebutyl peroxybenzoate, lauroyl peroxide, ketone peroxide, tert-butyl peroxy-2-ethylhexanoate, methyl ethyl ketone peroxide, cyclohexanone peroxide. . The amount of these catalysts used is 10% of the ethylenically unsaturated monomer for addition polymerization.
The amount is usually 0.01 to 5 parts by weight, preferably about 0.05 to 3 parts by weight.

Examples of organic solvents used in solution polymerization include toluene, benzene, xylene, hexane, heptane, n-octane, inoctane, ethyl acetate, ethyl acetate, methyl ethyl ketone, methanol, ethanol, and ingbanol. From the viewpoint of polymerization workability, toluene alone or a mixed solvent containing 50% by weight or more of toluene is preferable. The amount of these organic solvents used is usually 5 to 900 parts by weight, preferably 25 to 400 parts by weight of iTi, per 100 parts by weight of the acrylic polymer.

Note that, depending on the type of organic solvent, chain transfer of monomers may easily occur, and due to this, the desired graft body may not be formed and good elastic properties may not be obtained. In particular, if the molecular weight of the acrylic polymer is low, it is difficult to expect improvement in elastic properties. Therefore, it is desirable to set the amount of organic solvent to be used within an optimal range, taking into account the type of solvent and the molecular weight of the acrylic polymer.

On the other hand, when performing bulk polymerization, there is a risk of gelation during the polymerization operation, and this gelation not only makes the polymerization operation difficult but also has an adverse effect on the moldability of the resulting addition polymerized polymer. Therefore, when bulk polymerization is employed, it is generally desirable to use an appropriate chain transfer agent to control the molecular weight. In particular, when selecting and using an acrylic polymer with a relatively high molecular weight, the use of the chain transfer agent is essential.

As such chain transfer agents, conventionally known ones such as thioglycol, thioglycolic acid, butyl mercaptan, lauryl mercaptan, and decyl mercaptan can be widely used. The amount used is generally 0.01 to 100 parts by weight of the ethylenically unsaturated monomer for addition polymerization.
It may be 1 part by weight, preferably 0.03 to 0.6 parts by weight.

The graft polymer obtained in this way is
(2) A homopolymer or copolymer consisting of a partially unreacted acrylic polymer and an ethylenically unsaturated monomer may be included, but even in such a case, the gel fraction of the entire polymer is substantially VCIO%. It is desirable that it be kept below. If it is higher than the above, it is not preferable because it may cause problems in moldability and other problems.

Further, the above-mentioned graft polymer has an elastic modulus measured by the above-mentioned method that is substantially in the range of 5 to 200 kyA2, particularly preferably 10 to 100 kyA2, and has a It has a higher elastic modulus. In addition, as in the case of the gel fraction above, the term "substantial" may include unreacted acrylic polymers and homopolymers or copolymers that do not participate in addition polymerization; It means elastic modulus.

An acrylic elastomer is obtained by blending the above-mentioned graft polymer with a coloring agent of a color depending on the purpose, and if necessary, a filler and known additives such as an ultraviolet absorber i. .

The basic rubber tape or sheet used in this invention is made by blending known synthetic rubber and/or natural comb with a coloring agent and various other known additives as necessary.
It is molded to a thickness of 5 to 2.00 mm.

The above-mentioned acrylic elastic material is formed in a layer on one side of the rubber tape or sheet to a thickness of 0.05 to 2.0011 parts. When forming this elastic body layer, there are methods such as forming an acrylic elastic body in advance into a sheet shape and pressing it under pressure on a rubber sheet, or coating it and drying it.

A rubber pressure-sensitive adhesive layer is formed on the other side of the rubber tape or sheet having the acrylic elastic material layer formed on one side in this way, resulting in the coated tape or sheet of the present invention.

This pressure-sensitive adhesive shoulder is made of a rubber tape or a com-based pressure-sensitive adhesive that is mainly made of known rubber and/or synthetic resin, and is blended with a coloring agent depending on the purpose and various other known additives as necessary. It is coated onto a sheet to a thickness of 0.05 to 2.0 OfIn.

The coated tape or sheet of the present invention thus obtained can be wrapped around the surface of a pipe in a sushi roll shape or a spiral shape, with the acrylic elastic layer facing the outer surface.

At this time, this covering tape or sheet must be flexible;
No welts are formed on the lamp part. Also,
This coated tape or sheet has sufficient elasticity because the acrylic elastic layer formed on one side is unvulcanized.
There are no cracks on the surface of the tape or sheet, and since this elastic material has weather and heat resistance comparable to that of vulcanized rubber, deterioration of the base rubber due to sunlight is prevented and the pipe It exhibits excellent anti-corrosion properties and is resistant to discoloration.

Next, examples of this invention will be described. In addition, in the following, parts mean parts by weight.

Example I Ethylene-propylene-ethylene norbonene rubber 1
00 parts, zinc white 7 parts, stearic acid 15 parts, thiuram vulcanization accelerator 20 parts, thiazo/silica vulcanization accelerator 0.3 parts, naphthenic grosses oil 8 parts, titanium white 8 parts, sulfur 1 part and Lid 1': A blended composition consisting of 7 parts of 1 cyanine green was formed into a sheet with a thickness of 0.5 mm.
A vulcanized rubber sheet was obtained by press vulcanization at 60°C for 30 minutes.

A blended composition consisting of 60 parts of n-butyl acrylate, 40 parts of ethyl acrylate, 5 parts of acrylic acid, and 02 parts of azobisisobutyronitrile was polymerized in ethyl acetate, and a 40% ethyl acetate solution of the acrylic polymer was added. Obtained. The elastic modulus of this acrylic polymer is 1.5 kg//cm2
, MW was 540,000.

This polymer solution was kept at 40°C, 50 parts of methyl methacrylate and 04 parts of benzoyl peroxide were added to 100 parts of the acrylic polymer, and after purging with nitrogen for 2 hours, the solution was heated to 85°C for 4 hours. The mixture was stirred to obtain an ethyl acetate solution of the acrylic graft polymer. The elastic modulus of this graft polymer is I 8 kf, 4
It was ++2.

Next, add and stir dioctyl phthalate 1. to the polymer solution at a ratio of 3 parts to 100 parts of the graft polymer. It was coated to a thickness of 0.5 mm and dried by heating to obtain a vulcanized rubber sheet on which an acrylic elastic layer was formed.

On the other side of this rubber sheet, add 100 parts of butyl rubber, 20 parts of polybutene, 35 parts of petroleum resin, 35 parts of oil, 100 parts of calcium carbonate, and 5 parts of phthalocyanino green.
A rubber-based pressure-sensitive adhesive consisting of 300 ml of rubber was coated to a thickness of 0.5 mm to obtain a coated sheet of the present invention.

Example 2 100 parts of styrene-butadiene rubber, 5 parts of zinc white, 1 part of stearic acid, 15 parts of thiuram vulcanization accelerator, 05 parts of thiazole vulcanization accelerator, 8 parts of naphthenic process oil
15 parts of titanium white, 1 part of sulfur, and 5 parts of phthalocyanine green were molded into a sheet with a thickness of 0.5 am, and press-vulcanized at +50'C for 30 minutes to obtain a vulcanized comb sheet. I got it.

85 parts of n-butyl acrylate, 15 parts of -rcrylonitrile
A blended composition consisting of 3 parts of acrylic acid and 3 parts of acrylic acid was subjected to emulsion polymerization by a conventional method, and the polymer was allowed to settle to obtain a lump of acrylic polymer. The acrylic polymer had an elastic modulus of 4.8 μ2 and a MW of 750,000.

100 parts of this acrylic polymer block was put into a 5e high viscosity polymer reactor, 70 parts of methyl methacrylate, 056 parts of benzoyl peroxide and 0,007 parts of lauryl mercaptan were added thereto, and the mixture was purged with nitrogen for 2 hours. The material was heated and kept at 90°C for 4 hours. The elastic modulus of the acrylic graft polymer thus obtained was l/1i25 and ring 2.

Add 100 parts of this graft polymer to 100 parts of dioctyl fucre-1.
・4 parts, phthalocyanine green 5 parts and titanium white 1 part
After adding 0 parts and stirring, heat press to a thickness of 0.5 m.
An acrylic elastic sheet of m was obtained.

This elastic sheet was pasted on one side of the above vulcanized rubber sheet by hot pressing. Furthermore, there is an example on the other side of this yyua rubber sheet! A com-based pressure-sensitive adhesive similar to that used in Q was applied to a thickness of 5 mm to obtain a coated sheet.

Example 3 100 parts of natural comb, 5 parts of zinc white, 15 parts of stearic acid,
Thiuram vulcanization accelerator 1.5 parts, thiazole vulcanization accelerator 06 parts, naphthene process oil 8 parts, titanium white 1
A blended composition consisting of 0 parts of sulfur, 1 part of sulfur, and 5 parts of phthalocyanine green was formed into a sheet with a thickness of 0.5 mm, and pressed at 160°C for 30 minutes to obtain a vulcanized comb sheet.

C) An ethyl acetate solution of acrylic graft polymer was applied to one side of the comb sheet in the same manner as in Example 1 so that the thickness after drying was 0.5 mm, and dried to form an acrylic elastic layer. A vulcanized comb sheet was obtained.

The other side of this rubber sheet was coated with the same rubber-based pressure-sensitive adhesive as in Example 1 to a thickness Q of 5 mm to obtain a coated sheet of the present invention.

Reference Example 1 The same rubber-based pressure-sensitive adhesive composition as in Example 1 was applied on one side of the same vulcanized rubber sheet as in Example 1 to a thickness of Q, 5 l1m.
A coated sheet was obtained.

Reference Example 2 The same rubber-based pressure-sensitive adhesive as in Example 2 was applied to one side of the same vulcanized comb sheet as in Example 2 to a thickness of 0.5 mm,
A coated sheet was obtained.

Reference Example 3 The same rubber-based pressure-sensitive adhesive as in Example 3 was coated on one side of the same vulcanized comb sheet as in Example 3 to a thickness of 05 mm,
Get the covering sheet.

Reference Example 4 5 parts of titanium white and 5 parts of phthalocyanine green were added to 100 parts of polyethylene to prepare a polyethylene sheet with a thickness of 1 mm. One side of this sheet was coated with the same rubber-based pressure-sensitive adhesive as in Example 1 to a thickness of 0.5 mm to obtain a coated sheet.

The following table shows the results of a weather resistance test and a water mold test performed on the coating sheets 11c obtained in Examples 1 to 3 and Reference Examples 1 to 4 above.

The test methods in the table above are as follows.

The covering sheet is shaped into a tape with a width of 50 am and an outer diameter of 50 am.
Example 1.2.3 was applied to a polished steel pipe with a length of 500 am.
and Reference Example I, 2.3 was stretched by about 10%, and Reference Example 4 was stretched by about 2%, and rolled half in half to form 2.
The specimen was left under normal conditions for 4 hours.

Weather resistance: Tested the sample with a Xanshaino type weather meter.
After irradiation for 000 hours, the presence or absence of clutches on the tape and the degree of discoloration were visually observed.

Mizumichi test: After the sample tape was immersed in water at 20°0 for 7 days, the state of water infiltration from the beginning and end of winding of the sample tape was observed.

As is clear from the above examples, the coated tape or sheet of the present invention has remarkable weather resistance and corrosion resistance. .

Claims (1)

[Claims] (1) On one side of the synthetic rubber and/or natural rubber sheet or tape, one or two types of homopolymer or copolymer that can have a glass transition temperature of 300° or higher and an acrylic polymer having viscoelasticity comparable to that of unvulcanized rubber. A coated tape comprising an acrylic elastic layer containing a graft polymer obtained by addition-polymerizing more than one ethylenically unsaturated monomer, and a rubber pressure-sensitive adhesive layer on the other side, or sheet.