JP2687131B2 - Flame-retardant synthetic leather and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flame-retardant synthetic leather, particularly to a synthetic leather suitable for a vehicle seat material.

[Conventional technology]

In recent years, as a method of imparting flame retardancy to synthetic leather, particularly to synthetic leather according to a dry process, it is known to add various flame retardants to each layer constituting the synthetic leather.

Further, synthetic leather generally causes brittleness and deterioration of the polyurethane resin by adding a flame retardant, and cannot be used for a long time even under normal use conditions.

On the other hand, the flame-retardant treatment of the synthetic leather according to the wet method has technical difficulties more than those of the dry synthetic leather, and since this is unsolved, to date, synthetic leather having durability and flame retardancy has not been obtained.

The specific contents of the technical difficulty of the flame-retardant treatment of wet synthetic leather are as follows. That is, even if a flame-retardant base material is subjected to a flame-retardant processing treatment, the flame-retardant agent is dissolved in water during desolvation and coagulation to form a microporous substrate in a wet treatment, and the effect is lost, and a microporous layer is formed. Even if a flame retardant is added to the polyurethane, the flame retardant will be dissolved in water when desolvated and solidified, and its effect will disappear.
There are three points that the wet film-forming performance is significantly reduced by adding a flame retardant.

BACKGROUND ART Polyurethane synthetic leather has been excellent in texture and appearance, and has been widely used as a material for bags, bags, shoes, clothing, belts and the like. However, conventionally, in most cases, as a raw material thereof, a polyurethane having a polyol component of a polyester having a glycol having 2 to 4 carbon atoms and a dibasic acid such as adipic acid is used.
Products with poor hydrolysis resistance that required long-term use, such as furniture and vehicle seats, could not withstand use at all.

Of course, adding an anti-hydrolysis agent, such as polycarbodiimide, to the component can make some improvement, but cannot expect substantial improvement. Especially when it is applied mainly to interior materials such as clothing, furniture, vehicle materials, etc., it is not practically applicable except for special ones because the legal regulations are strict because human damage is great at the time of fire. The legal regulations include, for example, FMVSS-302 of the American combustion standard for automobile interior materials and JIS D-1201 of Japan, and JIS A-1321 for wall coverings. There must be. In addition, automobile manufacturers often set their own standards that are stricter than the legal system. Moreover, in order to impart flame retardancy to synthetic leather as a composite material composed of fibers and synthetic resins, it is necessary to perform flame retardation treatment on both fibers and synthetic resins having different combustion mechanisms,
Generally, it is necessary to add a large amount of flame retardant in order to satisfy flame retardancy, but as a result, the texture is hardened, the durability is reduced, and a sticky feeling is generated. In addition to the feeling, problems such as bleeding or blooming phenomenon on the surface and deterioration of surface quality must be solved.

However, if a high-quality polycarbonate diol is used as the polyol component of the wet polyurethane, synthetic leather having excellent properties such as flame retardancy, hydrolysis resistance, light resistance and heat resistance can be obtained (Reference Example JP-A-63). -12769 gazette).

It is an object of the present invention to provide a synthetic leather having properties similar to those of a polycarbonate-based polyurethane synthetic leather using a general-purpose polypropylene glycol as a part of a polyol component, and a method for producing the same.

[Means for solving the problem]

To achieve the above object, the synthetic leather of the present invention has a microporous structure of polyurethane on a fibrous base material or a flame-retardant fibrous base material that has been subjected to a flame-retardant treatment, and has a polyurethane adhesive layer interposed therebetween. In a flame-retardant synthetic leather in which at least one or more polyurethane film layers are laminated on the microporous structure, the microporous structure contains a bromine-containing modified urethane compound and a crosslinking agent, and the mixing ratio of polycarbonate diol and polypropylene glycol is 90 / 10-60 / 40 (molar ratio) mixed diol as a polyol component, 100% modulus is 20
It is composed of polyurethane of 120 to 120 kg / cm ² , and one of the polyurethane film layers has a thickness of 20 to 80 μ as a skin layer or an outermost layer, and is composed of a polycarbonate polyurethane having a 100% modulus of 40 to 180 kg / cm ^2. .

The synthetic leather of the present invention comprises a flame-retardant fiber or a fibrous base material capable of flame-retarding treatment such as knitted fabric, woven fabric, and non-woven fabric, containing a bromine-containing modified urethane compound and a crosslinking agent, and polycarbonate diol and polypropylene glycol. Applying a polyurethane solvent solution containing a mixed diol as a polyol component,
After adhering using a means such as impregnation, a wet coagulation treatment is performed to form a microporous structure of the polyurethane on the fibrous base material, and a modified urethane compound containing antimony trioxide and bromine is formed on the surface of the microporous structure. An adhesive layer containing at least one polycarbonate-based polyurethane film layer is sequentially laminated, and either on the flame-retardant fibrous base material or on the fibrous base material flame-retarded prior to the step or during the step. It is obtained by forming a laminated structure of a flame-retardant adhesive layer and a film layer.

In the present invention, the fibrous base material includes a base material itself having a flame retardant property and a fibrous material such as a knitted fabric, a woven fabric and a non-woven fabric which is subjected to a flame retardant treatment. The flame retardant treatment can be performed prior to the manufacturing process or during the process.

The flame-retardant fibrous base material may be, for example, a polyester spun yarn or filament having flame retardancy obtained by copolymerizing a phosphorus compound as a flame retardant with a polyester, or a halogen compound, or by mixing and spinning, or a mixed fiber. Woven fabric, knitted fabric, non-woven fabric, etc. which are woven / knitted or entangled by using are used. This is the same even if the flame-retardant treatment is performed after processing the fibrous base material. After laminating the microporous structure, the microporous structure may be treated at the same time as making the microporous structure flame-retardant. An example of performing the flame retardant treatment in the subsequent steps will be described below.

First, natural fibers such as cotton and hemp, regenerated fibers such as rayon, suf, and acetate, synthetic fibers such as polyester, polyamide, and polyacrylonitrile, or fibers such as knitted fabrics, woven fabrics, and non-woven fabrics made of various blended fibers. The quality substrate is impregnated with polyurethane. The polyurethane impregnation amount is preferably within the range of 100% based on the weight of the fiber.

Further, a coating layer of polyurethane microporous structure is formed on the surface of the substrate on the impregnated cloth by wet treatment. A nonionic surfactant is generally known to be most effective as a coagulation regulator for forming micropores in a wet cell formed in a microporous structure. It should be noted that cellulose fine powder, calcium carbonate colorant, various stabilizers, etc. can be added for the purpose of improving the wet film-forming property and texture of this polyurethane, but the kind and the amount of the additive are microporous. Careful decision is necessary in relation to the physical properties of the organization. Applying a solvent solution of polyurethane with these additives applied to a fibrous base material impregnated with polyurethane,
Coagulate and desolvate in water, repeat washing in warm water,
It is dehydrated and dried to form a microporous structure having fine pores on a fibrous base material. The polyurethane used for impregnation and coating is a polyurethane having a 100% modulus of 20 to 120 kg / cm ² with a mixed diol of polycarbonate diol / polypropylene glycol = 90/10 to 60/40 (molar ratio) as a polyol component.

If the 100% modulus is 20 kg / cm ² or less, the texture will be soft, but the physical properties will be weak and not practical, and 120 kg / cm ²
Although the physical properties are improved by the above, the texture becomes hard, which is not preferable.

 The density of the microporous structure is preferably 0.3 to 0.7 g / cc.

If the density is 0.3 g / cc or less, the physical properties are weak and not practical, and if the density is 0.7 g / cc or more, the texture becomes hard and it is not preferable.

Further, the thickness of the microporous structure is preferably 100 μm to 1000 μm. When the thickness is 100 μm or less, it is not preferable because it lacks flexibility and the volume feeling is poor, and when it is 1000 μm or more, the thickness becomes thick and wrinkles become large, which is not preferable.

As the chain extender, low molecular weight glycols such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol and neopentyl glycol, or piperazine,
Ethylenediamine, hexamethylenediamine, propylene-1,2-diamine, N-methyl-bis- (3-aminopropyl) amine, 1,4-diaminocyclohexane, 1-amino-3-aminomethyl-3,5,5- Primary or secondary aliphatic amines such as trimethyl cyclohexane can be used.

The flame retardant added to the impregnated and applied polyurethane elastomer solvent solution uses a bromine-containing modified urethane compound having a urethane bond in the molecule.

The amount of the flame retardant having a bromine content of 30 to 40% is preferably 10 to 30% by weight based on the polyurethane solid content.

If the amount added is less than 10%, the flame retardant effect cannot be expected, and if it is more than 30% by weight, the wet film-forming performance is significantly reduced.

As a method of post-treating the microporous structure with a halogenated phosphoric acid ester compound and a phosphorus-containing nitrogen-containing compound alone or in a mixture, any processing method such as an impregnation method, a coating method, or a gravure method may be used.

The rate of attachment of the flame retardant to the microporous structure and the fibrous base material is preferably 5 to 20% by weight. The reason for limiting the adhesion rate is that the flame retardant may indirectly cause deterioration of the polyurethane elastomer.

As the flame retardant added to the polyurethane adhesive layer, a bromine-containing modified urethane compound having the same composition as the flame retardant added to the polyurethane which is previously impregnated or coated on the substrate is used.

The amount of the flame retardant having a bromine content of 30 to 40% is preferably 10 to 30% by weight based on the polyurethane solid content.

When antimony trioxide is used in combination with a bromine-containing modified urethane compound, it is combined with a bromine-based flame retardant at the time of combustion and is used in order to exhibit high flame retardancy due to a synergistic effect. Further, this also binds with a halogenated phosphoric acid ester-based compound during combustion to exert a synergistic effect.

It is preferable to add 30 to 60% of antimony trioxide to the bromine-containing modified urethane compound.

Further, in the present invention, 2 to 10 parts of a crosslinking agent is added to polyurethane during wet processing.

As the cross-linking agent, trimethylolpropane (TMP) and tolylene diisocyanate (TDI) adduct, TMP and hexamethylene diisocyanate (HMDI) adduct,
Adducts of TMP and isophorone diisocyanate (IPDI), trimers of HMDI, etc. can be used.

When the amount of the crosslinking agent added is 2 parts or less, the crosslinking density is low and the heat resistance is poor. On the other hand, if the addition amount is 10 or more, the crosslinking density becomes too large and hard, and the pot life becomes short, which is disadvantageous.

When a polyurethane film layer having a 100% modulus of 40 to 18 kg / cm ² is used as a film for coating the microporous structure, there are some difficulties in imparting the appearance of natural leather with fine wrinkles, , This is used for the mesothelial layer, and the surface has 100% modulus of 200-600kg / cm
By providing a polyurethane film layer having a yield value of ² and subjecting the formed polyurethane film layer as the outermost layer to a rubbing treatment, it is possible to increase the wrinkle residue and form an appearance that more closely resembles that of natural leather.

In this case, it is preferable that the coating layer used for the inner skin layer is colored with a coloring agent so that the outermost coating layer is not colored and is a transparent layer. The reason is that the outermost layer has an advantage that not only the wrinkle residue is imparted but also the discoloration and fading of the colorant due to light can be remarkably improved by not coloring the coating layer.

Specifically, on a substrate having a flame-retarded microporous structure, first, a polycarbonate polyurethane having a 100% modulus of 20 to 60 kg / cm ² containing an antimony trioxide and a bromine-containing modified urethane compound and having a thickness of 10 to 10 A polycarbonate-based polyurethane adhesive layer is formed by laminating 60 μm. In this case, the polycarbonate-based polyurethane used for the adhesive layer may be a copolymer in which a part of the polycarbonate-based polyol in the constituent components is replaced with a polyether-based polyol such as polytetramethylene glycol or polypropylene glycol.

Further, a polycarbonate polyurethane having a 100% modulus of 40 to 180 kg / cm ² is laminated on the surface of the adhesive layer as a coating layer with a thickness of 20 to 80 μm. When the outermost layer is separately provided by using this as the inner skin layer, the polycarbonate-based polyurethane adhesive layer and the polycarbonate-based polyurethane inner skin layer are formed to have the same modulus and thickness as those of the polyurethane adhesive layer and the polyurethane film layer, and further, the outermost layer is formed on the inner skin layer surface. 100% modulus 200-600kg / cm ² as outer layer
A polycarbonate-based polyurethane film layer having a yield value is laminated to form a layer having a thickness of 5 to 10 μm.

Incidentally, the above-mentioned inner skin layer, the polycarbonate-based polyurethane used for the outermost layer, as the diisocyanate that reacts with the polycarbonate-based polyol, any of yellowing type, hardly yellowing type and non-yellowing type can be used. Considering the required light resistance, it is preferable to use a non-yellowing type diisocyanate.

When the polyurethane film layer is colored as the inner skin layer, coloring agents such as pigments and dyes, and various other stabilizer fillers can be added to this layer and, if necessary, to the adhesive layer because of the yellow color.

〔The invention's effect〕

As described above, the present invention is to form a microporous structure mainly composed of synthetic leather by using polypropylene glycol in addition to polycarbonate diol in the polyol component of the wet polyurethane, and to make all microporous structures polycarbonate-based. Although it is inferior in thermal stability and mechanical strength compared to the one made of polyurethane, in addition to using both components together, the drawback is compensated by the addition of a cross-linking agent, which has a texture and feel very similar to natural leather and is flame-retardant. It is possible to obtain a synthetic leather having excellent heat resistance, hydrolysis resistance, light resistance, and heat resistance capable of withstanding a high temperature of 100 to 120 ° C. for a long period of time.

〔Example〕

Examples of the present invention will be given below, but the present invention is not limited to these examples.

(Example 1) On a single-sided raised cloth made of polyester / rayon fiber
Polyurethane with 100% modulus 40 kg / cm ² (polyol component is 1,6-hexane polycarbonate diol / polypropylene glycol = 70/30 (molar ratio)) Prepare the following coating solution consisting of solvent solution (solvent DMF). 1
It was applied to a thickness of m / m.

<Coating liquid> Parts by weight Polyurethane solvent solution (solid content 30%) 100 Crosslinking agent (Coronate HL solid content 75%; made by Nippon Polyurethane) 5 Bromine-containing modified urethane compound (solid content 70%, DFR-1001S, bromine content rate) 35%; made by Dainichi Seika) 8 Nonionic surfactant (Resamine CuT-190; made by Dainichi Seika) 1.5 Coloring agent (Dailac L color; made by Dainippon Ink) 5 DMF 100 The above coating liquid on one side raised cloth. After coating, it was coagulated and desolvated in water at 20 ° C, dehydrated and dried under hot air at 130 ° C to form a microporous structure having a thickness of 0.95 m / m and excellent surface smoothness.

After that, a microporous structure containing a raised fabric is impregnated with a flame retardant composed of the following compounding liquid, and the wet pickup rate is 90%.
Squeeze to dryness, dry at 130 ° C for 3 minutes, then at 150 ° C for 2
The polyester / rayon fiber was flame-retarded by heat treatment for minutes.

<Flame retardant compound> parts by weight Phosphorus-containing nitrogen compounds (Frame Guard VF-74; made by Dainippon Ink & Chemicals, Inc.) 10 Melamine resin 1.5 catalyst 0.1 water 90 On the other hand, 100% modulus 250kg with yield value on squeezed release paper / cm ² 1,6-hexanediol polycarbonate-based polyurethane solution (clear liquid containing no colorant)
Is coated with a knife coater to a dry thickness of 5 μm, and this is dried with hot air at 100 ° C. for 2 minutes to form a polyurethane film layer.

Next, a 100% modulus of 80 kg / cm ² was applied to the surface of the coating layer.
A 1,6-hexanediol polycarbonate-based polyurethane solution (containing 25 parts by weight of colorant) was applied with a knife coater to a dry thickness of 30 μ, and this was dried with hot air at 100 ° C. for 3 minutes to form a polyurethane middle layer. Formed.

Furthermore, the 100% modulus on the surface of the mesothelial layer is 27 kg / cm.
² of 1,6-hexanediol polycarbonate - a polyurethane adhesive polytetramethylene glycol copolymer by the following formulation dry thickness was coated with a knife coater so as to 45Myu.

<Adhesive compounding> Parts by weight Polyurethane solution (solid part 40%) 100 Antimony trioxide 6 Bromine-containing modified urethane compound (solid content 70%, DFR-1001S bromine content 35%; Dainichiseika) 14 100 ° C After hot-air drying for 3 minutes at 40 ° C., the surface of the microporous tissue formed on the napped cloth is faced to the upper surface of the polyurethane adhesive layer, thermocompression bonded at 140 ° C., and bonded.
The release paper was peeled off to obtain a synthetic leather.

When the resulting synthetic leather is subjected to a wrinkle treatment with a machine, it not only retains the wrinkle for a long time, but also retains the wrinkle for a long time, and its texture and appearance are very similar to those of natural leather. It passed FMVSS-302, was excellent in hydrolysis resistance, light resistance, and heat resistance, and was suitable as a vehicle seat material.

(Comparative Example 1) A synthetic leather was obtained in the same manner as in Example 1, except that the crosslinking agent was not added to the formulation of the coating solution.

(Example 2) As a flame-retardant fibrous base material, a double-sided brushed fabric made of flame-retardant polyester fibers obtained by copolymerizing polyester with a phosphorus compound has 100% modulus of 40 kg / cm ² of 1,6-hexane. Diol polycarbonate polyurethane solvent solution (solvent
DMF) is mixed and impregnated with an impregnating liquid having the following composition,
Squeeze roll was used to squeeze the polyurethane solid content to 25% based on the weight of the fiber, and then this was immersed in water at 20 ° C, coagulated, desolvated, dehydrated, and dried under hot air at 130 ° C to obtain an impregnated cloth. .

<Impregnation liquid formulation> parts by weight Polyurethane solvent solution (solids 30%) 100 Bromine-containing modified urethane compound (solids 70%, DFR-1002S bromine content 31%; made by Dainichiseika) 10 Nonionic surfactant (Resamine CuT-190; made by Dainichi Seika) 1.5 Colorant (Dailac L color; made by Dainippon Ink) 10 DMF 230 Polyurethane with 100% modulus of 50 kg / cm ² (polyol component as a coating liquid for forming a microporous structure) 1,
6-hexane polycarbonate diol / polypropylene glycol = 60/40 (molar ratio)) Prepare the following coating solution consisting of a solvent solution (solvent DMF), and apply it to the above impregnated cloth with a thickness of 1.1 m / m did.

<Coating liquid formulation> Weight part Polyurethane solvent solution (solid part 30%) 100 Crosslinking agent (Coronate EH, solid content 100%; made by Nippon Polyurethane) 4 Bromine-containing modified urethane compound (solid content 70% DFR-1002S, bromine content rate) 31%; made by Dainichi Seika) 10 Nonionic surfactant (Resamine CuT-190; made by Dainichi Seika) 1.5 Coloring agent (Dylac L color; made by Dainippon Ink) 5 DMF 110 Apply the above coating solution on the impregnated cloth. After that, it was coagulated and desolvated in water at 20 ° C., dehydrated and dried under hot air at 130 ° C. to obtain a microporous fiber substrate having a thickness of 1.2 m / m and excellent surface smoothness.

On the other hand, 100% modulus is 90kg / cm on release paper with diaphragm.
² of 1,6-hexanediol polycarbonate polyurethane solution (colorant 20 parts by weight containing) dry thickness was coated with a knife coater so that the 40 [mu, polyurethane film layer which was 3 minutes air drying at 100 ° C. Formed.

Furthermore, the 100% modulus on the surface of the coating layer is 20 kg / cm.
² , 6-hexanediol polycarbonate polyurethane adhesive (polyurethane solution solid content 40%, 100 parts by weight)
5 parts by weight of antimony trioxide and 15 parts by weight of a modified bromine-containing urethane compound) were applied with a knife coater to a dry thickness of 30 μm and dried with hot air at 100 ° C. for 3 minutes, and then the polyurethane adhesion The surface of the above-mentioned microporous structure was bonded to the upper surface of the layer by thermocompression bonding at 150 ° C., and then the release paper was peeled off to obtain a synthetic leather.

The obtained synthetic leather has passed the American combustion standard FMVSS-302 and has excellent hydrolysis resistance, light resistance and heat resistance,
The appearance was also very similar to natural leather, and it was suitable as a vehicle seat material.

(Comparative Example 2) A synthetic leather was obtained in the same manner as in Example 2 except that the crosslinking agent was not added to the formulation of the coating solution.

For the synthetic leathers obtained in Examples 1 and 2 and Comparative Examples 1 and 2, the US Combustion Standard FMVSS-302 was used under the following conditions.
Table 1 shows the combustion test results, hydrolysis resistance, and light resistance test results according to.

Combustion test method Combustion rate (inch / inch) that complies with American combustion standard FMVSS-302
Min) was measured.

Method of measuring hydrolysis resistance Synthetic leather sample pieces are left under conditions of 95% relative humidity and 70 ° C for 4 weeks, and then the resin layer of the sample pieces is loaded with a Taber abrasion tester under a load of 1 kg and the number of abrasions is 2000 The surface condition was observed by turning.

Light resistance measurement method Synthetic leather sample pieces were irradiated with a black panel temperature of 83 ° C for 200 hours with a fade meter, and then the resin layer of the sample pieces was surfaced with a Taber-type abrasion tester under a load of 1 kg and an abrasion count of 2000. The condition was observed.

Measuring method of heat resistance 400 pieces of synthetic leather sample is put in a gear type aging tester at 120 ℃.
After allowing to stand for a period of time, the surface state of the resin layer of the sample piece was observed with a Taber abrasion tester under a load of 1 kg and an abrasion count of 2000 times.

As is clear from Table 1 above, according to the present invention, synthetic leather having excellent hydrolysis resistance, light resistance and flame retardancy could be obtained.

Claims (2)

(57) [Claims] 1. A polyurethane film layer having a microporous structure of polyurethane on a fibrous substrate or a flame-retardant sustaining substrate which has been subjected to a flame-retardant treatment, and at least one or more polyurethane film layers via a polyurethane adhesive layer. In the flame-retardant synthetic leather laminated on the microporous structure, the microporous structure contains a bromine-containing modified urethane compound and a cross-linking agent, and the mixing ratio of polycarbonate diol and polypropylene glycol is 90/10 to 60/40 (mol. Ratio) mixed diol as a polyol component has a 100% modulus of 20 to 1
It is made of polyurethane of 20 kg / cm ² , and one layer of the polyurethane film layer has a thickness of 20 to 80 μ as a skin layer or the outermost layer, and 100% modulus is composed of a polycarbonate polyurethane of 40 to 180 kg / cm ^2. Flame-retardant synthetic leather. 2. A flame-retardant fiber or a fibrous base material capable of being flame-retarded such as knitted fabric, woven fabric, and non-woven fabric, which contains a bromine-containing modified urethane compound and a crosslinking agent, and contains polycarbonate diol and polypropylene glycol. After applying a polyurethane solvent solution containing the mixed diol as a polyol component by a means such as coating and impregnation, a wet coagulation treatment is performed to form a microporous structure of the polyurethane on the fibrous base material. An adhesive layer containing antimony trioxide and a bromine-containing modified urethane compound on the surface of the organic structure, and at least one or more polycarbonate-based polyurethane coating layers are sequentially laminated, and the flame-retardant fibrous base material or prior to the step, or the step Flame-retardant synthesis characterized by forming a laminated structure of an adhesive layer and a coating layer, both of which have flame-retardant properties, on a fibrous base material that has become flame-retardant on the way. Method of manufacturing the leather.