JPH0233384A - Synthetic leather of good feel - Google Patents

Abstract

PURPOSE:To obtain the title flexible synthetic leather excellent in durability by laminating a base fabric with a surface skin material consisting of a polyurethane containing a specific group and having specific physical properties with an adhesive consisting of a crosslinkable polyurethane. CONSTITUTION:A release paper is coated with a polyurethane surface skin material 10-100kg/cm<2> in 100% modulus prepared by reaction between (1) a diol containing >=5wt.% of a polymeric diol carrying a group of formula I, (2) an organic diisocyanate and (3) a chain extender followed by hot drying to form a polyurethane film followed by thereon coating an adhesive prepared from (4) a diol containing >=5wt.% of a group of formula II (R<1> is methyl, etc.; R<2> is H, methyl, hydroxymethyl, etc.; n+m>=2), (5) an organic diisocyanate and (6) a crosslinking agent. Thence, the resultant sheet is laminated with a base fabric comprising natural or synthetic fiber followed by hot-air drying, thus obtaining the objective flexible, durable synthetic leather of good feel.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to synthetic leather with improved hand.

[Conventional technology]

Synthetic leather whose skin material is polyurethane is! ! Because of its good fit and appearance, it is used in large quantities in a wide variety of applications, including as a material for shoes, clothing, furniture, and vehicle seats such as automobiles. There is a strong demand for texture and durability for the synthetic leather, and in particular, requirements for qualities such as flexibility, heat resistance, hydrolysis resistance, light resistance, and mold resistance are becoming increasingly strict.

In order to meet these performance requirements, for example, the type and composition of polyurethane incorporated into synthetic leather has been changed. In addition, various studies have been conducted to satisfy the above-mentioned performance requirements by selecting fiber base materials for synthetic leather, multilayering adhesive layers and skin layers, and combinations thereof.

For example, Japanese Patent Publication No. 55-23956 proposes a synthetic leather with excellent light resistance and hydrolysis resistance by disclosing a special polycarbonate-based polyurethaneurea elastom i-. 3 in JP-A-61-14221
It has been suggested that polyurethane using a polyester polyol such as -methyl-1,5-bentanediol and dicarboxylic acid has excellent mildew resistance, and that the polyurethane can be applied to synthetic leather. JP-A-62-2
No. 2817 discloses that polyurethane using a polymer polyol containing 2-methyl-1,8-octanediol units has excellent hydrolysis resistance, and that polyester-based polyurethane solutions containing the units are used as coating agents and impregnating agents. There is a disclosure that synthetic leather can be obtained by applying it to a substrate such as fiber.

Furthermore, in Japanese Patent Publication No. 59-1822, the adhesive layer is made of polyether polyurethane and the skin layer is made of polycarbonate polyurethane, which has excellent hydrolysis resistance and light resistance, and is durable for long-term use. It is said that synthetic leather can be obtained.

Furthermore, in JP-A-58-144185, a polycarbonate-based polyurethane adhesive layer, a polyester-based polyurethane intermediate layer made of glycol carboxylic acid having 4 or more carbon atoms, and a polycarbonate-based polyurethane skin layer are sequentially formed on a microporous composite fiber base material. A laminated flexible synthetic vehicle leather is disclosed.

[Problem to be solved by the invention]

However, polyester-based polyurethane is generally the most widely used, and synthetic leather that is fully satisfactory in all of its properties has not yet been obtained. Therefore, there is a strong desire for further expansion of the market, but this is currently unfulfilled.

The first object of the present invention is to provide synthetic leather that meets the various performance requirements described above.

A second object of the present invention is to provide a synthetic leather that has a good feel and is flexible.

Another object of the present invention is to make it possible to develop new uses for υ-layer synthetic leather by providing a new synthetic leather. Further objects of the present invention will become clear from the description below.

[A shortcut to solving problems]

As a result of intensive studies in view of the current situation, the inventors of the present invention discovered that a polymeric diol containing 5% by weight or more of a group represented by formula (1) % formula % (1) reacts with an organic diisocyanate and a chain extender. and the 100% modulus is lO~100kII/
- The adhesive layer is applied to the fiber base material as a skin material, a polyurethane prepolymer obtained by reacting a polymer diol and an organic diisocyanate as the main material, and a crosslinking agent as a curing agent. It was discovered that synthetic leather with a good texture and excellent hydrolysis resistance can be obtained by providing a skin layer on top.

First, the skin material used in the present invention will be explained in detail.

2-methyl-1,8-octanediol is preferable as the compound capable of producing the structural unit of the group represented by formula (I), and this compound is preferably used as the polymer diol in the present invention. As the diol residue, a polyester polyol or a polycarbonate polyol containing a group represented by formula (1) is preferable. These polymer diols will be described below.

Polyester polyols or polycarbonate polyols are made using 2-methyl-1,8-octanediol or mixed diols containing this diol.

Diols that can be mixed with 2-methyl-1,8-octanediol include ethylene glycol and 2-methyl-1,8-octanediol.
1,3-7'ropanediol, 1,4-butanediol, 3-methyl-1°5-bentanediol, 1,6-hexanediol, 1,9-nonanediol, dodecanediol, diethylenediol, neopentyl glycol, etc. However, in terms of flexibility, heat resistance, and durability, the larger the number of carbon atoms, the more preferable the diol is, and suitable diols have 6 or more carbon atoms, such as 1,6 hexanediol, 1,9-nonanediol, and dodecanediol. It is also perfectly acceptable to use a small amount of a polyhydric alcohol such as trimethylolpropane, glycerin, or pentaerythritol in combination with the above diol.

Polyester polyols are obtained by the reaction of the above-mentioned diols and dicarboxylic acids.

The structural unit of the dicarboxylic acid is preferably of the formula (I [[) and / is the formula (■). In the formula (III), n represents an integer of 1-12, and examples of aliphatic dicarboxylic acids that can produce the formula (Ill) include succinic acid, glutaric acid, adipic acid, azelaic acid, sepatenoic acid, Examples include dodecanedioic acid. More preferred are adipic acid, azelaic acid, and sepatenoic acid. These dicarboxylic acids can be used not only individually but also in combinations of two or more. f&, in the above formula (IV), Ar has 6 carbon atoms
-lO divalent aromatic hydrocarbon residue, such as a phenylene group or a 7-tyrene group. Specific examples of aromatic dicarboxylic acids that can produce the formula (Ill/) include terephthalic acid, inphthalic acid, orthophthalic acid, 1,5-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid,
Examples include 2.6-7tale dicarboxylic acid and any mixture thereof. More preferred are terephthalic acid and isophthalic acid. Further, the aromatic dicarboxylic acids and their argylester derivatives can also be used as the dicarboxylic acid source.

There are no particular restrictions on the method for producing the polyester polyol, and known polyester a polymerization means can be applied. For example, structural units (1), (III) and (I
V) is charged in a desired proportion and esterified or transesterified at 150 to 250°C in the presence or absence of an esterification and/or transesterification catalyst, and It can be produced by further subjecting the reaction product to polycondensation under high vacuum at 200 to 300°C.

Next, polycarbonate polyol is synthesized using the above-mentioned diol. (c) Synthesis method by transesterification of diol and sial carbonate or diaryl carbonate.Although there is a method of synthesis by transesterification of diol with sial carbonate or diaryl carbonate, any method synthesized can be used. Both the polyester polyol and the polycarbonate polyol have an average molecular weight of 600 to s, oo.

It is preferable that it is within the range of .

If the number average molecular weight of these polyols deviates significantly from the above range, the flexibility of the skin layer will be impaired, which is not preferable.

In the present invention, the organic diisocyanate used in the production of the polyurethane polyol used as a polymer having a group represented by the formula Includes aliphatic, alicyclic, and aromatic organic polyinsyanates. Examples thereof include 4.'4'-diphenylmethane diisocyanate, p-)unilene diisocyanate, toluylene diisocyanate), 1,5-naphthylene diisocyanate, isocyanate, xylylene diisocyanate, hexamethylene diisocyanate, inphorone diisocyanate), 4
．． 4-dicyclohexylmethane diisocyanate is mentioned. Among them, 4,4-diphenylmethane diisocyanate or inphorone diisocyanate is preferred.

Chain extenders also include those commonly used in the polyurethane industry, ie, compounds containing at least two hydrogen atoms capable of warping with incyanates. Examples include ethylene glycol, 2-methyl-1,3
-,7'ropanediol, 1,4-butanediol, 1
．． 6-hexanediol, xylylene glycol, 3-
Methyl-1,5-bentanediol, bishydroxyethoxybenzene, neopentyl glycol, 2-methyl-1,8-octanediol, 1,9-nonanediol, inphoronediamine, hydrazine, dihydrazide, trimethylolpropane, Examples include glycerin and the like.

Among them, ethylene glycol, 1,4-butanediol,
Inphorondiamine and the like are preferred.

The method for producing the polyurethane serving as the skin material in the present invention is as follows. A polymeric diol and an excess organic diisocyanate are reacted to produce a prepolymer having terminal incyanate, and then a chain extender such as a diol or diamine is reacted to form a polyurethane. The urethanization reaction may be carried out without a solvent, or may be carried out in a solvent that is inert to incyanate groups. As the solvent in this case, dimedelformamide, toluene, methyl ethyl ketone, tetrahydrofuran, methyl acetate, etc. can be used.

In this way, polyurethane for skin materials is made from polyester polyol or polycarbonate polyol, diisocyanate, and chain extender, but it is necessary that this polyurethane contains a component having the structural unit of formula (1). This is because the polyurethane having the structural unit represented by formula (I) has a large number of carbon atoms (9), has side chains, has a low glass transition temperature, and inhibits crystallinity. When used as a skin material, it is thought that synthetic leather can be obtained that has excellent hydrolysis resistance and cold resistance, and is extremely flexible and has a good texture. This effect is due to the fact that the component represented by formula (I)
It is necessary to contain more than 5 parts by weight, and if it is less than 5 parts by weight, there is no effect.

Polyester polyol t-+ having a group represented by formula (1) is polycarbonate polyol alone or a mixture thereof; or these polyols and formula (1)
It is also possible to use it in combination with an ether polyol such as polyester polytetramethylene glycol, polypropylene glycol, or polyethylene glycol, which does not have the group represented by. In this case, a mixture of these polyols may be reacted with a diisocyanate and a chain extender, or a mixture of two or more of the nine obtained by reacting each polyol with a diisocyanate and a chain extender may be used. It's okay. In either case, it is necessary that the polyurethane contains 5 or more groups represented by formula (1) by weight.

In the present invention, the epidermal layer has a 100% modulus of 1
It needs to be between 0 and 100 kr/-. If it is less than 10 y/-, the wear resistance will be poor, and the reverse K l 0
If it exceeds 0 kf/-, the effect of using a flexible base material containing formula (1) will be lost. Care must be taken because this 100% modulus increases as the number of node segments increases.

Further, the skin layer may be used separately into an intermediate layer and a top layer (upper layer). In this case, it is desirable to use a flexible material with a low 100% modulus for the intermediate layer, and to use a polyurethane for the top layer that has a slightly high 100% modulus in view of abrasion resistance and is therefore hard.

If the middle layer and top layer are used separately, the middle layer can be foamed to make it even more flexible.

On the other hand, polyurethane for adhesives is polyurethane/tan resin...
], page 438, can be used. For example, polyester polyols obtained by combining diol and cyanodobonic acid, polyols such as polycaprolactone and borino (rerolactone), polyether polyols such as polycarbonate polyols, polytetramesolene gelylcol, polypropylene glycol, and polyetherene glycol. A polyurethane consisting of a main agent and a crosslinking agent obtained by reacting the above polymeric diol and an organic diisocyanate is used.

However, a polyurethane obtained by mixing two or more types of main ingredients obtained by reacting these polyols with an organic diisocyanate and combining this with a crosslinking agent may be used.

Here, the polyester polyol or polycarbonate polyol is ethylene glycol, 2-methy/l/-
1,3-propanediol, 1,4-butanediol,
3-Methyl-1,5-bentanediol, 1,6-hexanediol, 1,9-nonanediol, 2-mesol-1,8-octanediol, dodecanediol, diethylene glycol. It can be made using the same method as for the skin material described above.

Examples of organic diincyanates include known aliphatic, alicyclic, and aromatic organic polyincyanates containing two incyanate groups in the molecule, but especially 4,4'-diphenylmethane diisocyanate, p-)unilene di Isocyanate, toluylene diincibnate, 1,5-
Examples include naphthylene diisocyanate, xylylene diisocyanate, hexamethylene diisocyanate, inphorone diisocyanate, 4,4-dicyclohexylmethane diisocyanate, and the like.

Diisocyanates having incyanate groups having different reaction activities are preferred. In particular, isophorone diisocyanate or 2.4-1. Preferred are rundiisocyanates or mixtures containing them as main components. In addition to the above-mentioned organic dicyanate, a small amount of polyfunctional polyinsyanate such as trimethylolpropane or triinsyanate in which 3 mol of tolylene diisocyanate is added to 1 mol of glycerin can be added.

At this time, a suitable chain extender may be used if desired, and the chain extender may be a chain extender commonly used in the polyurethane industry, that is, a compound containing at least two hydrogen atoms capable of reacting with yrenanate. Included. Examples include ethylene glycol, 2-methyl-
1,3-propanediol, 1,4-nonanediol,
1,6-hexanediol, xylylene glycol, 3
-Mesol-1.5-bentanediol, bishydroxyethoxybenzene, neopentyl glycol, 1.9-
Examples include nonanediol, inphoronediamine, hydrazine, dihydrazide, trimethylolpropane, glycerin, and the like. Further, regarding the specific operation method for obtaining the above-mentioned polyurethane polyol, a known urethanization reaction technique is used. For example, number average molecular weight 60
A polyester polyol of 0 to 5,000 and a low molecular weight compound having optionally active hydrogen are mixed to form a polyester polyol of about 40 to 5,000.
After preheating to 100 ° C., add an organic diisocyanate in an amount such that the ratio of incyanate groups to the number of active hydrogen atoms of these compounds (NCOloH) is 1 or less,
It is obtained by reacting at 50-120°C for several hours. The above reaction may be carried out in the presence of an organic solvent inert to incyanate groups. If desired, conventional urethanization catalysts such as organotin compounds, tertiary amines, etc. may be used. When carried out in the presence of an organic solvent in a manufacturing plant, it is advantageous to determine the amount of organic solvent used so that the solids content of the final mixture is between about 10 and 90% by weight, preferably between 20 and 8,011%. be.

The polyurethane polyol obtained in this manner has a price of 3,000 to 70,000 in terms of performance when used as an adhesive.
The number average molecular weight is preferably .

The polyester polyol or polyurethane polyol used in the present invention preferably has at least two hydroxyl groups at the end of the molecule.

In the present invention, the adhesive is prepared by using the polyurethane polyol thus obtained as a main ingredient and blending as a crosslinking agent a compound having at least three groups that can react with the hydroxyl groups of this polyol.

Examples of the crosslinking agent used here include organic polyincyanates, epoxy resins, and mixtures thereof, and organic polyisonates are particularly preferred. Preferred organic polyisocyanates include compounds having three or more incyanate groups in the molecule, such as trimethylolpropane, glycerin, pentaerythritol, etc., in which all of the hydroxyl groups are replaced by tolylene diisocyanate or xylylene, and a crosslinking agent is used in the adhesive of the present invention. In this case, the blending ratio of the base resin and the crosslinking agent is preferably in the range of 1 to 20 in terms of equivalent ratio (NCOloH) of all incyanate groups in the crosslinking agent to all hydroxyl groups in the base resin, and a range of 1 to 10. If the equivalent ratio is less than 1, the heat resistance will be poor, and if it exceeds 20, the adhesive strength will decrease and flexibility will be lost. This originates from the stress concentration at the interface.

In this way, adhesives can be made of polymeric diols, organic diisocyanates, or other main ingredients used in ordinary synthetic leather, and polyurethane obtained from a crosslinking agent, but among these, polyurethane obtained from a crosslinking agent can be used. In order to obtain an excellent result, it is preferable to use a polyurethane containing a group represented by the following formula (II).

-O(CHz) n-C(CH2)m-0-(II
) (Here, R1 represents a methyl group or an ethyl group; R2
represents a hydrogen atom, a methyl group, an ethyl group, a hydroxymethyl group, or a hydroxyethyl group; m is n0m≧
2, preferably an integer that satisfies n0m≧4) Compounds that can form the structural unit of the group represented by formula (II), such as 2-methyl-1,3-propanediol, 3- Possible examples include methyl-1,5-bentanediol. Other diols to be used in combination with the compound capable of forming a group represented by formula (II) also preferably have carbon atoms of about 55 or more. This is because, in general, the larger the number of carbon atoms, the lower the glass transition temperature, and the better the hydrolysis resistance and heat resistance. However, the use of long-chain diols alone increases crystallinity and tends to result in a stale polyurethane. On the other hand, if a polyurethane having a group represented by the formula (If) is included, it is possible to obtain a polyurethane that is flexible as a whole and inhibits this crystallinity. Formula (II)
The group represented by
It is desirable that the content be equal to or more than - by weight.

It is preferable that the 100 timidulus of the polyurethane used as the adhesive layer is smaller than that of the skin layer.

Synthetic leather can be created, for example, by the following transfer method.

First, a solution of polyurethane for skin material is applied onto a deafening paper using a doctor knife and dried with hot air at 90 to 110°C for 2 minutes. The thickness of the resulting skin layer coating varies depending on the final use, but is usually 10 to 100 μm by adjusting the solution concentration and coating amount.

Next, an adhesive polyurethane solution is applied onto the skin layer, and a base fabric is laminated with a proper gap between laminating rolls and dried with hot air at 90-110°C for 2 minutes. If the adhesive polyurethane solution has a resin content of 30 to 50% by weight and is coated at 80 to 1509/rrl, an adhesive layer with a thickness of several tens of microns will be formed after drying.

Then lasing for 2-3 days at 40-60°C. Thereafter, the release paper is peeled off, and the same surface finishing as the gravure roll i is performed as necessary.

The base fabric can be a knitted fabric obtained from synthetic fibers, such as polyamide, polyester, vinylon, polyacrylonitrile, etc., semi-synthetic fibers, such as rayon, cupro, acetate, etc., or natural fibers, such as silk, wool, cotton or linen.
Any of woven fabrics, nonwoven fabrics, impregnated fabrics, etc. can be used. Of course, the type and material of the base fabric are important factors that determine the texture of synthetic leather.

Further, in the production of synthetic leather, polyurethane is sometimes used as a finishing agent on the surface, but the polyurethane used as the skin material in the present invention can also be used as a finishing agent. In this case as well, it is preferable to use a polyurethane having a group represented by formula (II).

Incidentally, it is also possible to color the adhesive and/or the polyurethane for the snoring skin material by mixing a pigment or dye. You can dye it after making it into synthetic leather.

〔Example〕

Hereinafter, this will be specifically explained in Examples.

In the same table, the flexibility was compared and judged by touch.

◎ Very good ○ Good Δ Slightly hard
The surface stickiness, surface cracks, and peeling of the skin layer that occur when left for 5 to 10 weeks in an atmosphere of (jungle test condition) were evaluated.

◎ Very good ○ Good Slightly bad × Very bad (Example of synthetic leather production) Using a knife coater on release paper, apply a polyurethane solution for the skin layer (solid content concentration 20%) to a dry thickness of 25 μmK.
The polyurethane film is formed by coating the polyurethane film by heating and drying it at 100°C for 3 minutes. Next, 120 t of polyurethane solution for adhesive (solid content concentration 40%) was applied on the skin layer.
/d coating using a knife coater,
Immediately, the non-raised sides of the raised fabric, which is a blend of Tetoron as the warp and rayon as the weft, are pasted together and pressed together using a laminating roll. After drying at 100°C for 2 minutes, it is aged at 50°C for 3 days.

When two layers, a top layer and an intermediate layer, are provided as skin layers, dry films are formed from polyurethane solutions for the top layer and the intermediate layer sequentially on release paper.

Examples 1 to 10 Synthetic leathers were obtained using polyurethane consisting of polyester diol, organic diisocyanate, and chain extender as the skin material, and having the configurations shown in Table IK according to the synthetic leather preparation examples described above.

The flexibility and hydrolysis resistance of the obtained synthetic leather were measured, and the results are also shown in Table □. All synthetic leathers had good texture and flexibility.

Examples 11 to 18 Using polyurethane containing polycarbonate diol, organic diisocyanate, and chain extender as the skin material,
The results when synthetic leather was obtained in the same manner as in Example 1 are shown below.
It was shown to. All synthetic leathers had good texture and flexibility.

The relationship between abbreviations and compounds is as follows.

EG Ethylene glycol BD 1,4-butanediol HD 1,6-hexanediol MPD 3
-Methyl-1,5-bentanediol ND 1,
9-nonanediol MOD 2-methyl-1,8-octanediol I
PDA Isophoronediamine PCL Polycaprolactone PMVL Polymethylvalerolactone PBA Polybutylene adipate PTG Polytetramethylene glycol PPG
Polypropylene glycol IPDI HDI TDI Di Inphorone diisocyanate Hexamethylene diisocyanate Tolylene diisocyanate 4.4-Diphenylmethane diisocyanate TMP (T
DI)s TMP(HDI)s TMP(IPDI)3 Trimethylolpropane tolylene diisocyanate adduct, trimesololpropane hexamethylene diisocyanate adduct, trimethylolpropane inphorone diisocyanate adduct HC Polyhexamethylene carbonate (invention) effect)

Claims (8)

[Claims] (1) In polyurethane obtained by reacting a polymeric diol with an organic diisocyanate and a chain extender,
Polyurethane in which the polymeric diol contains 5% by weight or more of a group represented by the formula (I) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I) and has a 100% modulus of 10 to 100 kg/cm^2. Synthetic leather that uses polyurethane, which is obtained by reacting a main ingredient obtained by reacting a polymeric diol and an organic diisocyanate with a crosslinking agent, as a skin material and as an adhesive. (2) The synthetic leather according to claim 1, wherein the polymer diol containing the group represented by formula (I) is a polyester diol or a polycarbonate diol. (3) The synthetic leather according to claim 1 or 2, wherein the adhesive is polyurethane containing 5% by weight or more of the group represented by formula (II) in the main ingredient. ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (Here, R^1 represents a methyl group or an ethyl group, and R^
2 represents a hydrogen atom, a methyl group, an ethyl group, a hydroxymethyl group, or a hydroxyethyl group. Also, n and m are integers that satisfy n+m≧2) (4) Any one of claims 1 to 3, wherein the skin material consists of an intermediate layer and an upper layer, and the 100% modulus of the polyurethane used in the upper layer is higher than the 100% modulus of the polyurethane used in the intermediate layer. Synthetic leather described in . (5) The synthetic leather according to any one of claims 1 to 4, wherein the skin material consists of an intermediate layer and an upper layer, and the intermediate layer is a foam layer. (6) The synthetic leather according to any one of claims 1 to 5, characterized in that a polyurethane for skin material is used as a finishing agent. (7) The synthetic leather according to claim 3, wherein the group represented by formula (II) is ▲ has a mathematical formula, a chemical formula, a table, etc. ▼. (8) The synthetic leather according to claim 1 or 2, wherein the polymeric diol constituting the adhesive is a polyester polyol having a ▲ mathematical formula, chemical formula, table, etc. group.