JP2838923B2 - Sealing material joining material - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tape or sheet-like seal material, and more particularly to a seal material joining material based on a crosslinked polyamide used for joining an end portion of a heat-shrinkable seal material.

[0002]

2. Description of the Related Art Tapes and sheet-like sealing materials (hereinafter, simply referred to as sealing materials) made of a polymer material, particularly a heat-shrinkable polymer material, include wires, power cables, water and sewage, city gas, and the like. Used for various purposes such as pipes for crude oil transportation, pipes such as various pipelines for factory plants, anticorrosion coatings for connecting parts of various marine structures, etc., and coating and sealing of their ends. I have. In particular, for large-diameter pipes such as pipelines, sheet-shaped heat-shrinkable sealing materials are used instead of conventional heat-shrinkable tubes used for coating small-diameter pipes such as cables. These sealing materials were usually held together by an adhesive applied to their ends. However, there are various problems in the workability of the adhesive and the like, and other materials for joining the sealing material have been proposed. For example, Japanese Patent Publication No. 61-7937 discloses a method of joining the ends of a heat-shrinkable sheet material, an adhesive product and an adhesive composition used for the method.

In particular, a heat-shrinkable sealing material shrinks by heating and adheres to an adherend or the like, but a bonding material used for the heat-shrinking sealing material is mainly joined to the sealing material by heating before the sealing material shrinks. It is necessary to join the seal materials to each other and to tightly fix and hold the seal materials even during subsequent heat shrinkage. Therefore, various polymers that are stable and do not melt at the shrinkage heating temperature of the sealing material are used as a base or a part of the bonding material. In the above publication, polyolefins, polyamides, polyvinyl halides, polyaryl ketones, polyfluorocarbons, cross-linked polyethylene and the like are mentioned as preferable, but conventionally, heat-shrinkable sealing materials and bonding materials thereof, Conventionally, most of the polymer used for coating the straight portion other than the connection portion of the pipe is made of polyethylene.
However, in recent years, there has been a tendency to transport crude oil or the like at a high temperature of 90 ° C. or higher in a pipeline, or to transport the crude oil at a high pressure in the middle of the pipeline to improve transport efficiency. Therefore, polypropylene,
2. Description of the Related Art A heat-resistant polymer material such as polyamide has been used for a straight portion of a pipeline. In this case, it is naturally necessary to use a sealing material made of a heat-resistant material such as polyamide in the connection portion, and development of a joining material therefor is desired.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a bonding material for bonding the above-mentioned heat-resistant sealing material, in particular, a heat-resistant, heat-shrinkable sealing material, and to examine the crosslinking of a polyamide polymer. However, the present invention was completed based on the finding that the crosslinked polyamide can be more suitably used as a joining material for a heat-resistant sealing material.

[0005]

According to the present invention, there is provided a sealing material joining material characterized in that a crosslinked polyamide obtained by adding and mixing a crosslinking accelerator to a polyamide polymer and irradiating with an electron beam is used as a base. Is provided.

Further, there is provided a sealing material joining material in which an adhesive layer comprising a heat-softening polymer and a pressure-sensitive adhesive is laminated on a substrate constituted by integrally bonding the above-mentioned crosslinked polyamide with a reinforcing material. You.

[0007]

The sealing material joining material of the present invention is constituted as described above, and its base is a crosslinked polyamide obtained by adding and mixing a crosslinking promoter to a polyamide polymer and crosslinking by electron beam irradiation. Thus, the elasticity is increased at a temperature higher than the melting point of the resin or higher, and various sealing materials such as a heat-shrinkable sealing material can be stably bonded and held.

Hereinafter, the present invention will be described in more detail. In the present invention, the polyamide-based polymer is used after being crosslinked. Generally, the effect of the crosslinking of the polymer material is as follows. Increasing mechanical properties and preventing thermal deformation such as heat shrinkage and high temperature creep can be mentioned. It is known that a polymer material containing a polyamide-based polymer is generally difficult to crosslink by irradiation with radiation or addition of an organic peroxide. However, it is well known that crosslinking is effected by adding a crosslinking accelerator such as a polyfunctional monomer having two or more double bonds. Considering the physical properties and the like of these crosslinked polyamide-based polymers, the application of the heat-resistant sealing material as a joining material was made for the first time by the inventors.

[0009] The polyamide-based polymer in the present invention comprises:
Typical examples include nylon 6, nylon 6, nylon 9, and nylon 11 of nylon 6, and nylon 66 and nylon 610 of nylon 66. In addition, an elastomer may be added to these polyamide-based polymers, if necessary, in consideration of the flexibility after crosslinking. Examples of the elastomer include a synthetic rubber such as ethylene-propylene rubber and butyl rubber, and an ionomer. The added amount of the elastomer is preferably about 5 to 30% by weight based on the polyamide polymer.

Various crosslinking accelerators have been conventionally known. As the crosslinking accelerator to be added to the polyamide-based polymer, an allyl ester of a polybasic acid is preferable. Further, diallyl maleate, N, N '-Methylenebisacrylamide, triallyl cyanurate (TAC),
Triallyl isocyanurate (TAIC) and triallyl phosphate (TAP) are particularly preferred. When these polybasic acid allyl esters are added to and mixed with the polyamide-based polymer and irradiated with an electron beam without being added, 50 Mrad or more is required to obtain 50% or more as a gel fraction value indicating the degree of crosslinking.
While the above dose is required, the polyamide polymer can be highly cross-linked by irradiating a small dose of electron beam. The addition amount of the crosslinking accelerator is preferably about 2% by weight to 5% by weight based on the polyamide-based polymer. The amount of addition can be appropriately selected in consideration of the predetermined degree of crosslinking and the irradiation amount of the electron beam within the above range. If the addition amount of the crosslinking accelerator is less than about 2% by weight, a large dose of electron beam is required, which is not preferable. When the amount exceeds 5% by weight, the degree of crosslinking does not further increase even if the irradiation amount of the electron beam is increased.

In the present invention, the dose of electron beam irradiation after the addition of the crosslinking accelerator may be extremely small compared to the case where no crosslinking accelerator is added as described above, and may be about 3 to 20 Mr.
ad is enough. If it is less than about 3 Mrad, a sufficient crosslinking effect cannot be obtained, and even if irradiation exceeds 20 Mrad, an increase in crosslinking cannot be expected. The crosslinked polyamide obtained by adding a crosslinking accelerator to the above polyamide-based polymer and irradiating it with an electron beam has a significant decrease in elongation, but a remarkable modulus (elastic modulus) at 100% elongation at high temperature, for example, 230 ° C. improves. Therefore, in the present invention, the bonding material based on the crosslinked polyamide having an increased modulus is elastic against temporary elongation when the sealing material is bonded, or in the case of a heat-shrinkable sealing material, when the sealing material contracts due to heating. This is preferable because bonding can be maintained.

The above-mentioned crosslinked polyamide can be used as a joining material for a joining portion of a sealing material by providing an adhesive layer by applying an adhesive and a pressure-sensitive adhesive to itself. Further, it is preferable that the reinforcing member is formed integrally with the reinforcing material as described below and used as a reinforcing member for joining a sealing material. A specific example of a sealing material joining material using the above crosslinked polyamide will be described with reference to the drawings. However, the joining material of the present invention is not limited by these drawings. FIG. 1 is a sectional explanatory view of a sealing material bonding panel according to one embodiment of the present invention in which a reinforcing material and an adhesive layer are integrally bonded to a crosslinked polyamide as a base. In FIG. 1, a sealing material joining panel 1 is obtained by integrally joining and forming a crosslinked polyamide layer 2, a reinforcing material layer 3, and an adhesive layer 4. As the reinforcing material, single or mixed fibers such as inorganic fibers such as glass fibers and mineral fibers, organic fibers such as animal fibers, plant fibers and plastics, and nonwoven fabrics and woven fabrics of these fibers can be used. Lamination of the reinforcing material and the crosslinked polyamide can be performed by heating and / or pressing integrally with the adhesive layer.

For the adhesive layer, it is preferable to use a cross-linked hot-melt adhesive comprising a mixture of an adhesive thermosoftening polymer and a pressure-sensitive adhesive. As the adhesive thermosoftening polymer, a copolymer of ethylene and a polar monomer of an unsaturated ester or acid is used. Examples of polar monomers of unsaturated esters or acids include vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, butyl isobutyrate, and vinyl benzoate; methyl acrylate, ethyl acrylate, methyl methacrylate, and methacrylic. Examples thereof include unsaturated acid alkyl esters and aryl esters such as ethyl acrylate, n-butyl acrylate, phenyl acrylate, methyl crotonate and ethyl crotonate, and acrylic acid and methacrylic acid. Preferably, a copolymer of ethylene and vinyl acetate, a copolymer of ethylene and ethyl acetate, and a terpolymer of ethylene, vinyl acetate, and acrylic acid or methacrylic acid are used. As the pressure-sensitive adhesive for the adhesive layer, various pressure-sensitive adhesives such as rubber-based, acrylic-based, and vinyl-based can be used.

If necessary, an antioxidant or a crosslinking accelerator is added to the mixture of the adhesive thermosoftening polymer and the pressure-sensitive adhesive.
After irradiation and cross-linking at a dose of 5 to 30 Mrad by electron beam irradiation or the like, it can be laminated with the above-mentioned reinforcing material and laminated on one surface of an integrated reinforced cross-linked polyamide laminate by coating or the like. The sealing material joining panel configured by laminating as described above may perform crosslinking of the polyamide resin and the adhesive layer separately, or after forming the laminate,
Crosslinking can also be carried out by electron beam irradiation or the like.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to embodiments. However, the present invention is not limited by the following examples.

Example 1 As a raw material of a crosslinked polyamide, a nylon 6 (235 ° C. melt flow rate (MF)) which is a polyamide resin composition conventionally used as a sheet for laminated steel sheets.
R) having a melt flow rate (MFR) of 12 to 18 at 15 to 21) and ethylene-propylene manufactured by Nippon Synthetic Rubber Co., Ltd. as a modifier for imparting flexibility. A composition comprising rubber, an ionomer, and TAC, TAIC or TAP as a crosslinking accelerator was kneaded at a composition ratio shown in Table 1 using a Belander mixer.

Next, each of the obtained kneading compositions was placed in a 30 mmφ extruder (THERMOPLA) at a set temperature of 230 ° C.
(STICS), melt-extruded, cooled with water, and then pelletized into pellets of 2 mmφ × 3 mm by a pelletizer (manufactured by Chuo Kikai). After drying the obtained pellets, the pellets were dried at a temperature of 230 using a hot press molding machine (manufactured by Shinto Metal Industry Co., Ltd.).
By compression molding at a temperature of 180 ° C., sheet-shaped test pieces of 180 × 180 × 1.0 mm were prepared. Each test piece was irradiated with an electron beam at room temperature in the air by a Van de Graaff type electron beam accelerator. The irradiation conditions were 3 passes at a speed of 5 m / min, the current was changed to 10, 20, and 30 mA, and the irradiation dose was set to about 5 Mrad, 10 Mrad, and 15 Mrad, respectively, and irradiation was performed. Manufactured. A test piece was punched out from each of the obtained test pieces with a dumbbell for a tensile test according to JIS K7113, and 150
The tensile strength tests at 230C and 230C were measured, respectively.
The results are shown in Table 1.

[0018]

[Table 1]

From the above results, it can be seen that Sample No. 7 of the non-irradiated
Compared to the case of laminated steel sheet for sealing material bonding timber, electron beam irradiation, crosslinked polyamides of the present invention, although there is decrease in the elongation at 0.99 ° C., at a high temperature say 230 ° C., even elongation and strength at break improve In particular, the 100% modulus is remarkably improved, and it can be seen that it is suitable as a joining material for various sealing materials, particularly a joining material for a heat-shrinkable sealing material. On the other hand, sample N
o. Just electron beam without adding a cross-linking accelerator as in 6
When exposed to the test piece becomes brittle, improvement in elastic modulus
The degree is low. This is presumed to be due to little intermolecular cross-linking.

Example 2 A nonwoven fabric having a thickness of 0.1 mm was added as a reinforcing material to the surface of the crosslinked polyamide of Sample No. 4 obtained in Example 1 above.
Heating and pressurizing to 230 ° C. gave a reinforced crosslinked polyamide piece. An adhesive layer made of a mixture of an ethylene / ethyl acrylate copolymer and a coumarone resin was formed on the surface of the non-woven fabric of the obtained reinforced crosslinked polyamide piece, to produce a laminated panel having the structure shown in FIG. FIG. 2 is a perspective explanatory view in which the laminated panel obtained as described above is applied to a joint of a sealing material covering a pipe weld joint. In FIG. 2, the obtained laminated panel 1 is applied on the bonding end 6 of a heat-shrinkable sheet 5 mainly composed of polyethylene, which is coated on a weld joint portion 8 of a pipe 7, on the adhesive layer side of the laminated panel. It pressed and joined.
Thereafter, the heat-shrinkable sheet 5 was shrunk by heating to 80 to 20 ° C. As a result, the heat-shrinkable sheet 5 was fastened and fixed around the pipe 7. On the other hand, also in the laminated panel 1, the heat-shrinkable sheet 5 was fastened and fixed without breaking, and no crack or the like was generated.

[0021]

The crosslinked polyamide of the present invention has an improved elastic modulus at high temperature and the like, and engages and reinforces a joining portion of a sealing material, especially a heat-shrinkable sealing material, thereby tightening the sealing material without breaking or cracking. It can be fixed and fixed, and is industrially useful.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a sealing material joining panel according to an embodiment of the present invention.

FIG. 2 shows a sealing material bonding panel according to an embodiment of the present invention.
It is a perspective explanatory view applied to joining of the sealing material which covered the pipe welding joint part.

[Explanation of symbols]

1 laminated panel 2 crosslinked polyamide
3 Reinforcing material 4 Adhesive layer 5 Sealing material
6 Seal material joining end 7 Pipe 8 Weld

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-57-11991 (JP, A) JP-A-59-12935 (JP, A) JP-A-59-11305 (JP, A) 7937 (JP, B2) (58) Field surveyed (Int. Cl. ⁶ , DB name) B29C 65/48-65/54 C08J 3/24 C09J 5/00-7/02 B29C 61/06-61/10

Claims (3)

(57) [Claims] An elastomer and a polyamide-based polymer.
After adding and mixing fine crosslinking promoter, obtained by irradiating an electron beam thereto
Sealing material bonding timber, characterized by the use of crosslinked polyamide as a base. 2. The method according to claim 1, wherein the polyamide-based polymer is nylon 6-based.
2. The sheet according to claim 1, wherein the sheet is nylon.
Lumber joining material. 3. Addition and mixing of nylon 6 and a crosslinking accelerator
After that, cross-linked nylon obtained by irradiating this with electron beam
6 using a sealing material as a substrate
Lumber.