JPS6039917B2 - Expandable tube for covering objects - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a foam tube for coating objects (hereinafter abbreviated as foaming agent tube) that can form a polymeric foam with good adhesion and appearance on the surface of objects to be coated, such as pipes and rods. related to)

In recent years, various products have been used for purposes such as insulation and heat retention, which are made by coating the outer periphery of pipes with polymeric foam. Covered pipes and other products have been well received.

Conventionally, this type of coating method has been put to practical use by extruding a polymer foam layer of a required thickness around the outer periphery of a metal pipe using an extrusion molding machine, or by using a polymer foam molded product that has been foamed and molded in advance. One method is to fit it into a metal pipe. However, all of these methods require separate dies and molds for a wide variety of metal pipes with complex shapes and different diameters, and are irrational. The present invention does not have these drawbacks, that is, it does not require a large number of dies or molds depending on the shape of the object to be coated, and the object is covered with the object and foamed by heating to improve its adhesion and appearance. It is an object of the present invention to provide a foamable tube that can be made into an excellent polymer foam.

That is, the present invention relates to a foamable tube made by bending and winding a foamable sheet molded product of a thermoplastic polymer mixed with and kneaded with a foaming agent into one or more layers, and bonding the peripheral edges. It is.

An example of this will be explained with reference to the drawings. Reference numeral 1 indicates a foamed sheet molded product, and dotted lines 2 indicate welded portions at the peripheral edges.

A foamable sheet molded product is a sheet-like polymer molded product that usually has a wall thickness of about 0.05 to 3 ribs, and when heated above the decomposition temperature of the foaming agent, it foams and becomes a polymer foam. refer to something.

This type of sheet molded product is made by adding a blowing agent and, if necessary, various additives such as a blowing agent, filler, colorant, anti-aging agent, stabilizer, crosslinking agent, and crosslinking aid to a thermoplastic polymer. After compounding and kneading using a mixing roll or an extruder, the foaming agent is molded into a sheet using an extrusion molding machine or a calendar molding machine at a temperature above the softening point of the thermoplastic polymer, at which no or most of the blowing agent decomposes. be able to. In the case of using an extrusion molding machine, it is preferable to mix the mixture and pelletize the ape product with a pelletizer before extrusion molding. Thermoplastic polymers used in the manufacture of the above foamable sheet molded products include polyethylene, chlorinated polyethylene, ethylene vinyl acetate copolymer, polypropylene, polystyrene, polyvinyl chloride, ethylene propylene terpolymer, nitrile rubber, butyl rubber, and acrylonitrile. -butadiene-styrene rubber, etc.

In addition, blowing agents to be added to these thermoplastic polymers include azo compounds such as azodicarbonamide and azobisisobutyronitrile, nitroso compounds such as dinitrosobentamethylenetetramine, paratoluenesulfonylhydrazide, - Examples include sulfonyl hydrazide compounds such as 4'-oxybisbenzenesulfonyl hydrazide, whose decomposition temperature is higher than the softening point of the thermoplastic polymer, and which hardly decomposes at all during extrusion molding. Select and use those that do not. Representative examples of foaming aids that can be used in combination with the above foaming agents include urea, metal salts of carboxylic acids, and the like. The amount of foaming agent and foaming aid used must be determined appropriately depending on the type of foaming heat-shrinkable tube so that a predetermined expansion ratio can be obtained when the foaming heat-shrinkable tube is foamed. The amount may be 1 to 2 parts by weight per 100 parts by weight of the plastic polymer. Specific examples of various additives that may be added as necessary include fillers such as talc, clay, silica, alumina, barium sulfate, metal powder, glass beads, and short glass fibers, and colorants such as titanium oxide, carbon, and Pigments and dyes such as Phthalocyanine Blue, Mapicoiero... (manufactured by Titan Kogyo Co., Ltd., trade name Shinkasha Red (manufactured by DuPont, trade name)) are used as anti-aging agents and stabilizers. Phenol, phenolic compounds such as salicylic acid, phenyl-8 naphthylamine, phenyl-Q
Amine compounds such as naphthylamine, peroxides such as dicumyl peroxide, lauryl peroxide, benzoyl peroxide, methyl ethyl ketone peroxide, etc. as crosslinking agents and crosslinking accelerators,
Examples include thiuram compounds such as tetramethylthiuram monosulfide, and dithiocarbamate compounds such as zinc dimethyldithiocarbamate and dithiocarbamate. The blending ratio of these various additives is usually such that the total amount is about 0.1 to 5 parts by weight based on 10 parts by weight of the thermoplastic polymer. The foamable tube of the present invention is obtained by bending the foamable sheet described above, winding it into one or more layers, and adhering the ends thereof.

The circumferential edges can be bonded, for example, by heat sealing or by using a suitable adhesive. When winding a single layer, it is also possible to attach fastener bears to both ends for binding. The foamed tube of the present invention thus obtained has a wall thickness of usually about 0.05 to 3 sides and has flexibility, and is used to coat the object to be actually coated. This is done in the following way.

That is, the object to be coated is first covered with a foamable tube, and then the tube is heated to a temperature above the softening point of the thermoplastic polymer to cause foaming. Due to this heating, the tube expands (foams) in a three-dimensional direction in a soft state, and the inner circumferential surface first firmly attaches to the coating object due to the expansion pressure caused by the foaming, and then the tube expands (foams) in a three-dimensional direction in a soft state. Expands in the outer direction, eventually forming a polymer foam with a predetermined expansion ratio that has good adhesion and appearance on the surface of the object to be coated,
The object to be coated will be coated with the foam.
As detailed above, the foamable tube of the present invention is made by bending a foamed sheet molded product, winding it into one or more layers, and gluing the circumferential ends, and even the inner diameter of the tube is not restricted. For example, the desired polymeric foam layer can be formed on the surface of the object by simply placing the tube above the object to be coated, heating and foaming it, and the regulation of the inner seat of the tube determines the length of the foam sheet. You can easily do it by just doing this.

Furthermore, according to the present invention, the object to be coated can be coated much more advantageously than the conventional method described above, which requires the use of many types of dies and molding molds depending on the shape of the object to be coated. The covering object, which is coated with a polymeric foam of a predetermined expansion ratio using the tube of the present invention, is endowed with various functions such as heat retention, insulation, cushioning, protection, and floating by the foam. It can be used for various purposes that make effective use of its functions.

In addition, in the present invention, an adhesive layer is provided on the inner surface of the foamed tube to produce a foamed laminated tube for covering an object (hereinafter abbreviated as foamed laminated tube).

This is advantageous because when it is applied to an article to be coated and heated and foamed, it adheres well to the article. A hot melt adhesive is particularly suitable for the adhesive layer.

This is because the foam tube can be easily applied to the article to be coated (for example, if a pressure-sensitive adhesive is used, it will easily stick to the surface of the article during the coating). The above-mentioned foamable laminated tube can be made, for example, by providing a hot-melt adhesive layer on one side of the foamable sheet molded product to form a foaming laminated tube, and then bending the tube with the adhesive layer inside to form one or more layers. It can be manufactured by winding it around the tube and gluing at least its local end.

Furthermore, in the present invention, a foamable laminated tube can be obtained by providing an adhesive layer, preferably a hot melt adhesive layer, on the inner surface of the foamable tube and a support layer on the outer surface.

In order to obtain such a foamable laminated tube, for example, a hot melt adhesive layer is provided on one side of the foamable sheet molded product and a support layer is provided on the other side to form a foamable laminated tube,
This can be manufactured by bending this with the adhesive layer inside to form one or more layers, and gluing the peripheral edges. The above-mentioned supporting layer is a polymer foam formed by heating and foaming a foamable sheet molded product layer, which is adhered more firmly to the surface of an object, and which has mechanical properties such as surface hardness and surface abrasion resistance of the polymer foam. Various resin sheets such as polypropylene, polyester, polyamide, and polyimide, nylon fiber cloth, and glass fiber cloth have the function of improving properties and imparting flame retardancy and weather resistance to the surface. , metal fiber cloth, silk cloth, nonwoven fabric, paper, asbestos, etc. can be suitably used.

The above-mentioned foamable laminated sheet can be produced, for example, by laminating a foamable sheet molded product and a sheet-like adhesive or a support layer using a laminating roll, hot press, or the like.

At this time, the support layer and the foamable sheet may be bonded together via a suitable adhesive. A foamable laminate sheet can also be made by melt multilayer extrusion. For example, a process in which a foamable composition made by blending and mixing a blowing agent with a thermoplastic polymer and a hot melt adhesive component are separately melt-extruded as two streams (the blowing agent in the foamable composition is heated at a temperature so that it does not decompose). It can be obtained by a melt extrusion method comprising a step of guiding these two flows into a single die, thermally bonding them in a molten state, and extruding the bonded material from the die. The present invention will be specifically described below using examples.

Note that parts in the examples are parts by weight.

Example 1 Ethylene pinyl acetate copolymer (manufactured by Mitsui Polychemical Co., Ltd.,
The blowing agent does not decompose a composition consisting of 10 parts of Evaflex PI907), 8 parts of a blowing agent (Celmic CAP, manufactured by Sankyo Kasei Co., Ltd.), and 1 part of a crosslinking agent (Dicumyl peroxide, manufactured by Nihon Yushi Co., Ltd.) Extrusion molding is performed under the following conditions to create a foamable sheet molded product (thickness: 0.8 mm, width: 4 mm).

After cutting the sheet molded product to an appropriate length, one end of the sheet is bent along the extrusion direction to the corresponding other end, and both ends are bonded together by thermal bonding, so that the inner diameter is 3. 2
A foamable tube with a thickness of 0.8 cm was obtained.

The resulting foam tube has an outer diameter of 3. A steel pipe with an inner diameter of 2.5 arcs and a length of 50 arcs was inserted into the gunwale, and the steel pipe was covered with the tube.

Thereafter, the tube was heated at 160 qo for 5 minutes to foam, and a polymer foam with excellent adhesion and appearance was formed on the surface of the steel tube. This foam had a foaming ratio of 1 needle and was excellent in heat insulation and cushioning properties. Example
2 Polyethylene (Mitsui Polychemical Co., Ltd., Mirason 11)
10 anchor parts, foaming agent, manufactured by Hyowa Kasei Co., Ltd., vinyl hole SW #7
)1 part of a crosslinking agent (dicumyl peroxide, manufactured by NOF Corporation), and 1 part of ethylene-vinyl acetate copolymer (manufactured by Mitsui Polychemical Co., Ltd., Evaflex #220). An adhesive resin composition consisting of Ikarikuni and Terben-based resin (Yasu Oil Co., Ltd., YS Resin P-1000) was melted by heating and simultaneously extruded using a two-layer extruder to give a thickness of 0.9 mm. It was made into a foamable two-layer sheet.

The thickness of the foamable resin layer was 0.8 mm, and the thickness of the adhesive resin layer was 0.1. After cutting the above-mentioned sheet to an appropriate length, the sheet was bent and glued in the same manner as in Example 1 so that the adhesive resin layer was on the inside.
Thickness 0. A foamable laminated tube with rough skin was obtained.

This tube is an aluminum tube (outer diameter 2mm, inner diameter 1.6mm)
The tube was inserted into the aluminum tube by inserting an arc (length 50 cm). Thereafter, the foam was heated at 20,000° C. for 5 minutes to form a polymer foam, which had an adhesive resin layer in the inner layer and had very good adhesion to the aluminum tube and an excellent appearance. Example 3 A foamable two-layer sheet consisting of the foamable resin layer and adhesive resin layer of Example 2 was used, and a glass fiber cloth (manufactured by Fuji Fiberglass Co., Ltd., CLENET G-
4400) was thermally bonded using a laminating roll to obtain a foamable three-layer sheet.

The above sheet was bent and bonded in the same manner as in Example 2 so that the adhesive resin layer was on the inside and the glass fiber cloth layer was on the outside to obtain a foamable laminated tube on the inner diameter 44 side. The resulting foamed laminated tube has an outer diameter of 3. Ratio x, inner diameter 2.5 skin,
A steel pipe with a length of 50mm was inserted to cover the steel pipe with the tube.

After that, it was heated at 200℃ for 5 minutes to foam.
Since the adhesive resin layer is on the inner layer, it has very good adhesion to the steel pipe, and its surface is covered with glass fiber cloth, making it possible to cover the foam with excellent wear resistance.

[Brief explanation of the drawing]

The drawing is a partially cutaway perspective view of a foam tube illustrating an example of the present invention. 1... Foamed sheet molded product, 2... Welded part.

Claims (1)

[Claims] 1. Foamed material for covering an object, which is obtained by bending and turning a foamable sheet molded product of a thermoplastic polymer blended with a foaming agent and kneaded into one or more layers, and bonding the peripheral edges. sex tube. 2 A foamable sheet molded product of a thermoplastic polymer mixed with a foaming agent and kneaded is bent and rolled to form one or more layers, and the peripheral edges are bonded to provide an adhesive layer on the inner surface of the foamable tube. A foamed laminated tube for covering objects. 3. The foamable laminated tube for covering an object according to claim 2, wherein the adhesive layer is a hot melt adhesive layer. 4 A foamable sheet molded product of a thermoplastic polymer mixed with a foaming agent and mixed with wires is bent and wound to form one or more layers, and the peripheral edges are bonded to form a foamable tube with an adhesive layer on the inner surface. A foamable laminated tube for covering an object, which is provided with a support layer on the outer surface. 5. The foamable laminated tube for covering an object according to claim 4, wherein the adhesive layer is a hot melt adhesive layer.