JP2000334902A - Polyethylene antiflaming laminated sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve weather resistance, heat fusion bonding workability and release strength by laminating polyethylene laminated layers each containing a phthalimide-based flame retardant on both surfaces of a woven knitted fabric using polyethylene flat yarns each containing a flame retardant as wefts and warps. SOLUTION: Polyethylene flat yarns each containing an aromatic bromine flame retardant such as a tetrabromobisphenol A, a decabromodiphenylether, an octabromodiphenylether or the like are used as wefts and warps, densely woven and knitted to form a woven knitted fabric. Laminated layers each using a polyethylene such as a low-density polyethylene containing a phthalimide flame retardant and a weather resistant agent, a linear low-density polyethylene, an ethylene-vinyl acetate copolymer or the like are provided on both surfaces of the fabric to form the polyethylene antiflaming laminated sheet. Thus, weather resistance, heat fusion bonding workability and a release strength can be made excellent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyethylene flame-resistant laminate sheet suitably used as a curing sheet for construction work.

[0002]

2. Description of the Related Art Conventionally, as a flameproof sheet used for a curing sheet for construction, low-density polyethylene, linear low-density polyethylene, Polyethylene, ethylene-
A laminate sheet in which a laminate layer mainly composed of an acrylic acid ethyl ester copolymer, an ethylene-acrylic acid methyl ester copolymer, or the like is laminated, and each of the flat yarn and the laminate layer mainly contains decabromodiphenyl ether as a flame retardant. Is known.

[0003] Flame retardants containing decabrom diphenyl ether as a main component are known as one of the most effective flame retardants for polyethylene products at low cost, but the following problems are known. In other words, because it is easy to bleed, by heat welding after lamination, for example, edge processing of the sheet to fold back the edge,
In the splicing process in which the raw material is joined by heat welding, the welding surface is covered with the flame retardant, so that sufficient welding cannot be performed, or processing is performed at a very high temperature and pressure during welding. There were problems such as excessive shrinkage of the sheet. Due to the antagonism between decabrom diphenyl ether and the weathering agent, the weathering agent added with great care could not exhibit its original performance, and was not suitable for applications requiring weather resistance. Decabromodiphenyl ether has a heat resistance of 300 to 3
It was only 20 ° C., and the stable production temperature during laminating was 290 ° C. or less. For this reason, sufficient adhesive strength between the woven fabric and the laminate layer cannot be obtained, and when the thickness of the laminate layer is thin, a problem of interface peeling occurs, or the flame retardant stays inside the T die of the laminating apparatus at the time of switching the raw material. There was a problem that it disassembled and hindered the subsequent production.

[0004]

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a polyethylene flame-resistant laminate sheet having excellent weather resistance, heat welding processability and peel strength.

[0005]

According to the present invention, as a means for technically solving the above-mentioned problems, a phthalimide-based flame retardant is contained on both sides of a woven or knitted fabric using a polyethylene flat yarn containing a flame retardant as a weft yarn. This object is achieved by providing a polyethylene flame-resistant laminate sheet characterized by laminating a polyethylene laminate layer to be laminated.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
As the polyethylene used for the polyethylene flat yarn of the present invention, a resin such as high-density polyethylene, medium-density polyethylene, linear low-density polyethylene, low-density polyethylene, or a combination of two or more kinds is used. Among these, high-density polyethylene, which has an excellent stretching effect and provides high strength, is preferred. Melt flow rate of the above polyethylene (hereinafter referred to as MFR)
Is preferably 0.1 to 10 g / 10 min., And more preferably 0.5 to 5 g / 10 min.

As the flame retardant to be blended with the polyethylene flat yarn, a flame retardant such as a halogen-based, phosphorus-based or inorganic flame-retardant is used. Flame retardants are preferred, especially brominated flame retardants. Specific examples of the brominated flame retardant include aromatic brominated flame retardants such as tetrabromobisphenol A, decabromodiphenyl ether, octabromodiphenyl ether, bisdibromopropyl ether tetrabromosulfone, hexabromocyclododecane, and dibromoethyldichloromethane. Alicyclic brominated flame retardants such as bromocyclohexane, pentabromodiphenyl ether,
And liquid bromine-based flame retardants such as tetrabromodiphenyl ether. These may be used alone or as a mixture of two or more. Of these, decabrom diphenyl ether, which has an excellent flame retardant effect on polyethylene and is inexpensive, is preferred.

It is preferable to use a flame retardant auxiliary in combination with the bromine flame retardant from the viewpoint of improving the flame retardant effect. Specific examples of the flame retardant aid include antimony trioxide, antimony trichloride, and zinc oxide. The compounding ratio of bromine-based flame retardant / antimony-based flame retardant aid is 2/1 to 3 /
1 is preferred.

The blending amount of the brominated flame retardant and the antimony-based flame retardant auxiliary (hereinafter referred to as a flame retardant together) with respect to the polyethylene flat yarn is preferably 5 to 15% by weight of the flame retardant in polyethylene. Preferably, it is configured to contain 8 to 12% by weight of the flame retardant. If the amount of the flame retardant is less than 5% by weight, the flame retardant effect is not sufficient.
If it exceeds 15% by weight, the strength of the flat yarn is undesirably reduced.

As a method of blending the flame retardant, the flame retardant may be mixed with polyethylene and supplied directly to an extruder, or a master batch containing a high concentration of flame retardant in polyethylene in advance may be produced. Then, it may be supplied as this master batch.

In the method for forming a polyethylene flat yarn of the present invention, a mixture of polyethylene and a flame retardant is melt-kneaded by an extruder, and a film is formed by an inflation method or a T-die method. Among them, the T-die method is more preferable because the resin staying portion is small, the resin back pressure is low and the heat generation inside the machine is small, and the extruded film is rapidly cooled by a water cooling method. By rapidly cooling the film, the crystallinity of polyethylene is low, and the surface layer of the film is densified, so that the flame retardant hardly bleeds and the heat welding property is improved. Molding resin temperature is 250 ℃
The following is preferred. The film solidified by cooling
After slitting to a width of about 10 to 20 mm, the film is stretched and then heat-treated to form a flat yarn. The stretching treatment is performed at a temperature below the melting point of the polyethylene and above the softening point.
As the heating method, any method such as a hot roll type, a hot plate type, an infrared type, and a hot air type can be adopted. Among them, the hot roll type is preferable in terms of stretching efficiency, high-speed productivity, and stability.
The slit polyethylene film is heated and stretched by the peripheral speed difference between the front and rear rolls. The stretching ratio is preferably 3 to 15 times, more preferably 5 to 10 times. The single yarn fineness of the flat yarn is preferably 100 to 1
0000 denier (hereinafter abbreviated as d), more preferably 400 to 3000 d.

The thus obtained polyethylene flat yarn is densely woven and knitted as warp yarns to form a woven or knitted fabric. Weaving organization is not particularly limited, plain weave,
Twill weave, woven weave, etc. are adopted, but the gap is reduced,
Plain weave is preferred from the viewpoint of preventing misalignment. The driving density of the polyethylene flat yarn depends on the fineness of the single yarn, but is preferably 6 to 20 yarns / inch for both warp and weft yarns. The knitting structure is not particularly limited, and may be a flat knitted fabric or a warp knitted fabric.

A polyethylene flame-retardant laminated sheet is formed by providing a polyethylene laminate layer containing a phthalimide flame retardant and a weathering agent on both sides of the woven or knitted fabric.
Examples of the polyethylene used for the polyethylene laminate layer include low-density polyethylene, linear low-density polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and the like, alone or in combination of two or more. Used in combination. The MFR of the polyethylene is preferably 1 to 50 g / 10 min.,
More preferably, it is 5 to 30 g / 10 min.

The phthalimide-based flame retardant compounded in the polyethylene laminate layer is a compound represented by the following formula (1).

[0015]

Embedded image

(Wherein X represents a halogen atom.
Is an alkylene group having 1 to 6 carbon atoms, a is 0 or 1
And m and n represent an integer of 1 to 4. X in the above formula (1) is a bromine atom, R is an ethylene group, and m
And ethylenebis (tetrabromophthalimide) wherein n is 4 is preferred. Since the phthalimide-based flame retardant does not have an antagonistic effect with the weathering agent and exhibits the original performance of the added weathering agent, the weathering agent can be selected according to the purpose of use. Further, since the phthalimide-based flame retardant has excellent heat resistance, the melting temperature of the extruded laminate can be increased, so that the peel strength between the woven fabric and the laminate layer can be improved. Furthermore, since the phthalimide-based flame retardant does not cause bleeding, there is no inconvenience such as insufficient heat welding due to the bleeded flame retardant during the heat welding process.

It is preferable to use a flame retardant auxiliary in combination with the phthalimide-based flame retardant from the viewpoint of improving the flame retardant effect. Specific examples of the flame retardant aid include antimony trioxide,
Examples include antimony trichloride and zinc oxide.
The blending ratio of phthalimide-based flame retardant / antimony-based flame retardant aid is preferably 2/1 to 3/1.

In the present invention, the phthalimide-based flame retardant and the antimony-based flame retardant auxiliary (hereinafter collectively referred to as imide-based flame retardant) in the polyethylene laminate layer are preferably compounded in the polyethylene in an imide-based flame retardant. The material is configured to be contained in an amount of 3 to 10% by weight, more preferably 5 to 8% by weight. If the amount of the imide-based flame retardant is less than 3% by weight, the flame retardant effect is not sufficient, and if it exceeds 10% by weight, the flame retardancy is not further improved and it is not economical.

As a method of blending the imide-based flame retardant,
The imide-based flame retardant may be mixed with polyethylene and supplied directly to the laminating extruder, or a master batch containing a high concentration of imide-based flame retardant in polyethylene is manufactured in advance and supplied as this master batch. You may.

As the above-mentioned weathering agent, the following ultraviolet absorber or hindered amine light stabilizer is used.

As an ultraviolet absorber, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 5,5'-methylenebis (2-hydroxy-4-methoxybenzophenone) ), 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5'-t-octylphenyl) benzotriazole, 2- (2- Hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-t-butyl-
Benzotriazole UV absorbers such as 5'-methylphenyl) -5-chlorobenzotriazole, 2,2'-methylenebis (4-t-octyl-6-benzotriazole) phenol, resorcinol monobenzoate, 2,4- The
-t-butylphenyl-3'-5'-di-t-butyl-4'-hydroxybenzoate, hexadecyl-3-5-di-t-butyl
And benzoate ultraviolet absorbers such as -4-hydroxybenzoate. The blending ratio of the UV absorber
0.05 to 5% by weight based on polyethylene,
More preferably, it is 0.1 to 1% by weight.

As hindered amine light stabilizers, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1, 2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) di (tridecyl) -1,2,3,4-butanetetracarboxylate, 1- (2-hydroxyethyl) -2,2,
Polycondensate of 6,6-tetramethyl-4-piperidinol and diethyl succinate, 1,6-bis (2,2,6,6-tetramethyl-4-piperidylamino) hexane and 2,4-dichloro-
And polycondensates of 6-tertiary octylamino-s-triazine. The compounding ratio of the light stabilizer is preferably 0.05 to 5% by weight, more preferably 0.1 to 1% by weight, based on polyethylene.

As a method of laminating a polyethylene laminate layer on both sides of the previously formed woven or knitted fabric made of polyethylene flat yarn, an extrusion lamination method using a mixture obtained by adding the above flame retardant and weatherproofing agent to the above polyethylene is used. It is good to laminate with. Although the thickness of the polyethylene laminate layer can be arbitrarily set, it is preferably 20 to 60 μm, and more preferably 30 to 50 μm for use as a curing sheet for construction.
m is more preferred.

The sheet obtained by laminating the polyethylene laminate layer on both sides of the woven or knitted fabric in this manner is usually bent at the edges and heat-bonded for post-processing since it is used for a curing sheet for construction or the like. Is applied. As the thermal bonding method, a known method such as a high frequency welding method, an ultrasonic welding method, or a hot air welding method can be employed. However, the hot air welding method is preferable as a method of thermally bonding the inner surfaces of the folded sheet edges.

The sheet obtained in this manner is
It is preferable to have a performance that meets the flameproof standard specified in ISL1091.

The polyethylene used in the present invention includes an antioxidant, a lubricant, an antistatic agent, a pigment, an inorganic filler, a flame retardant, a crosslinking agent, without departing from the scope of the present invention.
Additives such as a foaming agent and a nucleating agent can be blended and used.

[0027]

EXAMPLE High-density polyethylene (MFR = 1.0 g / 1)
0 min., Density = 0.956 g / cm ³ ), using a master batch in which a brominated flame retardant decabrom diphenyl ether and antimony trioxide were mixed at a ratio of 3: 1 to blend 8 wt% as a flame retardant. , This is 65mmφ
Was extruded into a film using a T-die method at a melting temperature of 250 ° C. using an extruder, and cooled by a water bath method to form a film. This film was slit to a width of 20 mm and then stretched by a hot roll method at a stretching ratio of 9 to obtain a flat yarn having a fineness of 1450 denier (hereinafter abbreviated as d). This flat yarn has a tensile strength of 6.2 g / d and an oxygen index of 2
It was 5. Using this flat yarn, 8 ×
A plain weave fabric was formed at a drive density of 8 threads / inch. A low-density polyethylene (MFR = 8.0 g / 10 min., Density = 0.918) was formed on both sides of the woven fabric thus obtained.
g / cm ³ ) of a phthalimide-based flame retardant ethylenebis (tetrabromophthalimide) and antimony trioxide in a ratio of 3: 1.
6% by weight as an imide-based flame retardant and 2- (3-t-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole (trade name:
Tinuvin 326) Using a mixture of 0.3% by weight and 2.5% by weight of pigment, a melt temperature of 32 was obtained by extrusion lamination.
A polyethylene laminate layer was laminated at 0 ° C. The thickness of the polyethylene laminate layer was 30 μm. The oxygen index of this polyethylene laminate layer was 25. The oxygen index of this polyethylene flameproof laminated sheet is 28
Met. In the flame contact test according to JIS L1091, the number of flame contacts was 4.8 on average and passed. Further, the tensile strength of the polyethylene flame-resistant laminated sheet is 112 k in length.
g / 5 cm, width 110 kg / 5 cm and sufficient strength, and sufficient peel strength between the woven fabric and the laminate layer was obtained. Weather resistance is weatherometer irradiation 800H
The residual tensile elongation after r was 90%, which was good. Next, the polyethylene flame-resistant laminated sheet was subjected to edge processing by folding back the edge of the sheet using a hot air center sealing machine manufactured by Japan High Frequency Co., Ltd. to perform thermal bonding. The heat bonding temperature was 330 ° C., and a product with good edge processing without bleeding of a phthalimide-based flame retardant was obtained.

[0028]

As described above, according to the present invention, a polyethylene-based flat yarn is blended with a brominated flame retardant which is excellent in dispersibility and does not reduce the flat yarn strength and has an excellent flame-retardant effect. Having a phthalimide-based flame retardant that has heat resistance, does not interfere with post-processability due to bleed, and does not have an antagonistic action with weathering agents, increases weather resistance, heat welding processability, and peel strength. An excellent polyethylene flameproof laminate sheet was obtained.

Claims (1)

[Claims] 1. A polyethylene flame-retardant laminated sheet comprising a woven / knitted fabric using a polyethylene flat yarn containing a flame retardant as a weft, and a polyethylene laminate layer containing a phthalimide-based flame retardant laminated on both surfaces.