JP6328157B2 - Production method of flame retardant honeycomb screen - Google Patents

Description

    The present invention relates to a method for producing a flame retardant honeycomb screen.

A method of forming a honeycomb-shaped material (Patent Document 1) and a honeycomb screen (Patent Document 2) are disclosed.
Window shield by pre-creased and pre-folded continuous strip of material with linear adhesive, cut it into lengths, stacks it, and applies pressure and heat A stretchable honeycomb screen suitable for use as a body is made.

  It has been conventionally known that the addition of a flame retardant such as a halogen compound or a phosphorus compound is effective for making an organic material flame retardant. And combined use of phosphorus and halogen, phosphorus and nitrogen have a synergistic effect, and a more effective flame-retardant effect is obtained (Non-patent Document 1).

JP-A-6-50068 Japanese Patent Application Laid-Open No. 6-221064

`` Flame Retardant Finishing, Editor-in-Chief Joseph C. Salamone, Shizuo Kubota, Polymeric Materials Encyclopedia, Vol. 4 (F-G), p. 2386, CRC Press (1996) ''

Conventionally, in the manufacture of honeycomb screens, there has been a problem that the adhesive strength is reduced when a flame retardant is added to the adhesive of the flame retardant fabric.
In addition, in application of a hot melt adhesive, the fluidity may be poor, and it has been necessary to set it to a high temperature. For this reason, there has been a problem of discoloration of the fabric.
When an additive is added to improve fluidity, a decrease in crepe strength and a decrease in flame retardancy are problems.

    In order to solve the problem that the adhesive strength decreases when a flame retardant is added to the adhesive of the flame retardant fabric, a flame retardant system that uses a hot melt adhesive having a high adhesive strength and reduces the amount of flame retardant added as much as possible is used. There is an improvement in adhesive strength due to the method of selection and cleaning of the substrate. Further, improvement of fluidity can be solved by adding a plasticizer and a lubricant. Furthermore, the problem of a decrease in crepe strength and a decrease in flame retardancy could be solved by providing a crosslinking step.

There are the following countermeasures for the problem of adhesive strength reduction.
In the manufacture of honeycomb screens using flame retardant fabric or flame retardant paper as a base material, a hot containing halogen flame retardant or phosphorus flame retardant or 5 to 15 weight percent of both halogen flame retardant and phosphorus flame retardant A method for producing a flame-retardant honeycomb screen, characterized by using a melt adhesive.

And there exists a manufacturing method of the flame-retardant honeycomb screen as described above characterized by using the hot-melt-adhesive containing a nitrogen element.
The hot melt adhesive containing nitrogen element has low combustibility from the beginning, the limiting oxygen index (LOI) is about 24 to 25, and the combined use of the nitrogen compound and the phosphorus compound has a synergistic effect on the flame retardancy. Flame retardancy is obtained at a concentration lower than the concentration of (Non-patent Document 1).

As a method for improving the adhesive strength, as a pre-process, a base material is added with a surfactant and washed with water to remove a softener or the like on the fiber surface. In addition, in the case of flame retardant paper or the like, it is possible to remove the chemicals adhering to the surface with compressed air or by suction.
That is, there is a method for producing a flame-retardant honeycomb screen as described above, which comprises a substrate washing step.

Furthermore, there are the following methods for improving flame retardancy and fluidity.
The flame retardant according to the above, wherein a hot melt adhesive containing 5 to 10 percent by weight of both the halogen-based flame retardant and the phosphorus-based flame retardant and containing 1 percent by weight or more of the phosphorus-based flame retardant is used. This is a method for manufacturing a honeycomb screen.
The coexistence of the halogen element and the phosphorus element has a synergistic effect, and flame retardancy is obtained at a concentration lower than a single concentration (Non-patent Document 1).
In addition, some phosphorus flame retardants act as plasticizers and improve fluidity.

There are the following methods for improving fluidity.
There is a method for producing a flame retardant honeycomb screen as described above, wherein a hot melt adhesive containing a plasticizer or a lubricant is used.

Furthermore, the following methods were able to solve the problem of the decrease in crepe strength and the decrease in flame retardancy.
There is a method for producing a flame-retardant honeycomb screen as described above, which comprises a crosslinking step.
The resin is thermally decomposed to produce a low molecular weight compound that is burned (Non-patent Document 1).
Therefore, when a crosslinking reaction occurs by using a moisture-curing polyurethane adhesive that crosslinks the isocyanate groups present in the polyurethane hot melt adhesive with moisture, or by adding a crosslinking agent, the flame retardancy is increased and the adhesive is bonded. Strength and crepe strength are also improved.

    As the base material, flame-retardant polyester fiber, polyester cotton blended fiber, acrylic fiber, polyamide fiber, cotton fiber, rayon fiber or other nonwoven fabric, woven fabric, knitted fabric or paper can be used.

Examples of the hot melt adhesive include polyethylene, polypropylene, ethylene-vinyl acetate copolymer (EVA), polyester, polyamide, modified polyvinyl alcohol, polyurethane, and moisture-cured polyurethane.
Nitrogen-containing hot melt adhesives include polyamide, polyurethane, and moisture-curing polyurethane.

  Examples of the flame retardant include inorganic types such as aluminum hydroxide, magnesium hydroxide, antimony trioxide (used in combination with a halogen type flame retardant), phosphorus type, and halogen type.

    Phosphorus flame retardants include aromatic phosphates such as triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, tricresyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate, butylated phenyl phosphate, propylated phenyl phosphate, Aromatic condensed phosphates such as resorcinol bis-diphenyl phosphate, resorcinol bis-dixylenyl phosphate, bisphenol A bis-diphenyl phosphate, tris (chloroethyl) phosphate, tris (β-chloropropyl) phosphate, tris (dichloropropyl) phosphate , Tetrakis (2-chloroethyl) dichloroisopentyl diphosphate, polyoxyalkylene bis (dichloroalkyl) phosphate Halogenated phosphoric acid esters such bets, polyphosphates, there is a red phosphorus-based or the like.

  Halogen flame retardants include tetrabromobisphenol A (TBBA), tribromophenol, ethylene bis (tetrabromophthalimide), TBBA carbonate oligomer, TBBA epoxy oligomer, brominated polystyrene, bis (pentabromophenyl) ethane, TBBA. -Bis (dibromopropyl ether), poly (dibromophenol), hexabromobenzene, chlorinated paraffin and the like.

Plasticizers and lubricants are added for the purpose of improving the fluidity of the molten hot melt adhesive, avoiding discoloration due to high temperatures, and improving workability such as coating.
As a plasticizer, dibasic acid such as dioctyl phthalate and dibutyl phthalate, dioctyl adipate, dioctyl sebacate adipic acid, sebacic acid ester, adipic acid, sebacic acid, phthalic acid and other dibasic acids and 1,2-propanediol , Polyesters with glycols such as butanediol, epoxidized vegetable oils such as epoxidized soybean oil and epoxidized linseed oil, trimellitic acid esters such as trioctyl trimellitate, phosphoric acids such as tricresyl phosphate and triphenyl phosphate There is an ester. Since it acts also as a flame retardant, it is preferable to use a phosphoric ester plasticizer.

As lubricants, hydrocarbons such as paraffin wax, synthetic polyethylene, liquid paraffin, stearic acid, behenic acid, fatty acids such as 12-hydroxystearic acid, stearyl alcohol, higher alcohols, stearic acid amide, oleic acid amide, erucic acid amide , Fatty acid amides such as methylene bis stearamide and ethylene bis stearamide, metal soaps such as calcium stearate, zinc, magnesium and lead, esters such as glycerin monostearate, glycerin monooleate, butyl stearate and octadecyl phosphate There are systems.
Also in this case, the lubricant containing phosphorus is preferable because it does not lower the flame retardancy.

    As for the cross-linking step, in moisture-cured polyurethane, a cross-linking reaction occurs with moisture in the air after applying the polyurethane hot melt adhesive. When a cross-linking agent having two or more functional groups is added to the hot melt adhesive, a cross-linking reaction occurs in the presence of an initiator such as a radical or a photo initiator depending on heat and light energy. For example, there are block isocyanate, epoxy compound, etc., bifunctional acrylate, polyfunctional acrylate, urethane (meth) acrylate, epoxy (meth) acrylate, ester acrylate and the like.

    Use of hot-melt adhesives with high adhesive strength for cleaning substrates, selecting flame retardant systems that utilize the synergistic effect of nitrogen and phosphorus, and halogen and phosphorus with low content, making it difficult for hot-melt adhesives The decrease in adhesive strength due to the addition of the flame retardant was suppressed. By adding a plasticizer and a lubricant, it was possible to bond at a relatively low temperature with good workability and to prevent discoloration of the fabric. And by the crosslinking process, the flame retardancy was improved, the adhesive strength and the crepe strength were improved.

実施例１〜５、比較例１〜５より、ポリエステル不織布についてはポリウレタン、ポリアミド、ＥＶＡ、湿気硬化ポリウレタンホットメルト接着剤の接着強度が高く、ポリエステルの接着強度は低い。ポリエステルホットメルト接着剤は溶融時に流動性が高く、付着量が少なくなるため、接着強度が低いと思われる。難燃剤５重量%の添加により、接着強度はそれほど低下しなかった。 Adhesive Strength of Hot Melt Adhesive Adhesive strength was tested according to JIS K 6854-2, “Adhesive Strength—Peeling Adhesive Strength Test Method—Part 2: 180 ° Peeling”. An adhesive film was sandwiched between two substrates having a length of 35 cm and a width of 2.5 cm, and hot pressing was performed at a temperature equal to or higher than the melting point, and bonding was performed at an adhesive surface of 15 cm × 2.5 cm. Substrate, polyester nonwoven fabric (weight per unit: 54.2 g / m2), number of samples: 5 points, test speed: 10 mm / min. The test environment was 20 ° C. and the relative humidity was 50%. A brominated aliphatic aromatic compound (melting point: 110 ° C., trade name: Pyroguard SR-720) was used as the flame retardant. The hot melt adhesive used was polyurethane (melting point 90 ° C.), polyamide (melting point 90 ° C.), polyester (melting point 97 ° C.), EVA (melting point 100 ° C.).

From Examples 1 to 5 and Comparative Examples 1 to 5, for polyester nonwoven fabrics, the adhesive strength of polyurethane, polyamide, EVA, and moisture-cured polyurethane hot melt adhesive is high, and the adhesive strength of polyester is low. Polyester hot melt adhesives are considered to have low adhesive strength because they have high fluidity when melted and less adhesion. By adding 5% by weight of flame retardant, the adhesive strength did not decrease so much.

Hot melt applicator (trade name Dynamini N05, manufactured by Dynatec Co., Ltd.) Using a nozzle base diameter of 0.6 mm, apply only one hot melt adhesive to the base material, length 35 cm, width 2.5 cm An adhesive was sandwiched between the two substrates, and hot pressing was performed at a temperature equal to or higher than the melting point for bonding. Tested by 180 ° peeling.
Urethane acrylate (bifunctional, average molecular weight 2.700, trade name NK oligo U-200PA) was used as a cross-linking agent, and 1-hydroxycyclohexyl phenyl ketone was used as a photoinitiator. After adhesion, irradiation was performed with a mercury lamp for 5 minutes.

The adhesive strength was improved by washing the substrate.
Cross-linking improved flame retardancy and adhesive strength. In addition, the creep strength was increased by crosslinking.
As for the base material, the polyester knitted fabric had higher adhesive strength than the woven fabric. This is considered to be due to the anchor effect that the adhesive enters the irregularities of the substrate.

難燃剤５重量%以上で、ＬＯＩは２７となり、接着剤は難燃性を示した。５重量%以下では、接着剤の難燃性は十分でなかった。そして、難燃剤１５重量%以上では接着強度の低下があり、実用的に問題であった。 Flame retardancy test The flame retardancy test was conducted according to JISK7201-2 "Flammability test with oxygen index". An adhesive film was sandwiched between two 6 cm × 15 cm base polyester nonwoven fabrics (weight per unit: 54.2 g / m 2), and heat-pressed to prepare test pieces (5 samples). The flame retardant is brominated aliphatic aromatic compound (melting point 110 ° C., trade name Pyroguard SR-720), and phosphorous is triphenyl phosphate (TPP), aromatic condensed phosphate ester, trade name PX-200. It was. The hot melt adhesive used was polyurethane (melting point 90 ° C.), polyamide (melting point 90 ° C.), polyester (melting point 97 ° C.), EVA (melting point 100 ° C.).
In the case of polyurethane, a limiting oxygen index (LOI) of 27 was obtained when 7.5% by weight of PX-200 was contained. When TPP was contained at 10% by weight, the LOI was 27, indicating flame retardancy.

When the flame retardant was 5% by weight or more, the LOI was 27, and the adhesive showed flame retardancy. Below 5 wt%, the flame retardancy of the adhesive was not sufficient. When the flame retardant is 15% by weight or more, the adhesive strength is lowered, which is a practical problem.

      Addition of a crosslinking agent including a photoinitiator to the adhesive and crosslinking in moisture-cured polyurethane improved flame retardancy, and improved adhesive strength and creep strength.

ＴＰＰの添加により、粘度は下がった。このことより、リン系難燃剤ＴＰＰ等の添加は溶融接着剤の流動性を良くすることが推認される。
可塑剤、滑剤をホットメルト接着剤に添加すると、流動性が良くなり、接着剤の融点より２０~３０℃高い温度１１０~１２０℃で塗布、接着できた。従って、基材の変色の問題が無くなり、また塗布も容易にでき、昇温時間も短くなり作業性が増した。
Viscosity Measurement After forming a hot melt adhesive into a film having a thickness of 1 mm, it was formed into a disk shape having a diameter of 2.5 cm, and TA Instruments Ltd. It was measured with a rheometer HR-2.

The viscosity decreased with the addition of TPP. From this, it is presumed that the addition of the phosphorus-based flame retardant TPP or the like improves the fluidity of the molten adhesive.
When a plasticizer and a lubricant were added to the hot melt adhesive, the fluidity was improved, and coating and adhesion were possible at a temperature of 110 to 120 ° C., which was 20 to 30 ° C. higher than the melting point of the adhesive. Therefore, the problem of discoloration of the base material is eliminated, the coating can be easily performed, the heating time is shortened, and the workability is increased.

Claims (3)

In the manufacture of a honeycomb screen using a flame retardant fabric or a flame retardant paper as a base material , a phosphorous system having a function as a plasticizer, containing 5 to 10 percent by weight of a mixture of a halogen flame retardant and a phosphorus flame retardant A method for producing a flame-retardant honeycomb screen, comprising using a hot-melt adhesive containing one or more weight percent of a flame retardant, which is a polyamide, polyurethane, or moisture-cured polyurethane containing nitrogen. It is characterized by using a hot-melt adhesive which is a polyamide, polyurethane or moisture-curing polyurethane containing a melting point of 110 ° C. or lower or a liquid flame retardant and having a melting point of 90 ° C. or lower or a liquid nitrogen element. A method for producing a flame retardant honeycomb screen according to claim 1 The method for producing a flame-retardant honeycomb screen according to claim 1 or 2, further comprising a crosslinking step of adding a crosslinking agent to the hot melt adhesive.