JP2021059794A - Synthetic leather - Google Patents

Abstract

To provide a synthetic leather suitably used for a glove, particularly for a glove for sports such as golf, which is manufactured by a dry coagulation method without using a large amount of solvent.SOLUTION: A synthetic leather comprises a polyurethane foam resin layer laminated on a fibrous base material. The polyurethane foam resin layer contains a plasticizer.SELECTED DRAWING: None

Description

The present invention relates to synthetic leather.

Conventionally, synthetic leather has been used as one of the materials for gloves. In particular, since flexibility and grip are required in applications such as sports gloves, synthetic leather manufactured by a so-called wet coagulation method is often used.

For example, in Patent Document 1, a substrate layer made of a polymer elastic material and a fiber-entangled non-woven fabric and a porous surface layer made of a resin mixture of a polyurethane resin, a linear ester urethane oligomer, and a fluorine-modified polyurethane are placed on the substrate layer. It discloses a leather-like sheet composed of. Further, in Patent Document 2, a laminate of a base fabric and an elastic synthetic leather having one or more resin layers and a reinforcing fabric is cut into various shapes of members of a target sewn product, and the laminate is used for reinforcement. Disclosed is a sewn product having elastic synthetic leather, in which elastic synthetic leather of various shapes is sewn after the cloth is peeled off.

Japanese Unexamined Patent Publication No. 2004-11041 Japanese Unexamined Patent Publication No. 2016-164316

However, the synthetic leathers of Patent Documents 1 and 2 are synthetic leathers produced by a wet coagulation method, and a large amount of solvent is used in the production process, so that there is a concern about environmental load.

The embodiment of the present invention has been made in view of such a current situation, and an object of the present invention is to use gloves, especially gloves, while being synthetic leather produced by a dry coagulation method that can be produced without using a large amount of solvent. Is to provide synthetic leather suitable for sports glove applications such as golf.

The synthetic leather according to the embodiment of the present invention includes a fibrous base material and a polyurethane foamed resin layer provided on the fibrous base material. The polyurethane foam resin layer contains a plasticizer.

According to the embodiment of the present invention, a synthetic leather produced by a dry coagulation method that can be produced without using a large amount of solvent, and yet suitable for gloves, particularly sports gloves such as golf, is provided. can do.

The synthetic leather according to the present embodiment is a synthetic leather formed by laminating a polyurethane foamed resin layer on a fibrous base material. That is, the synthetic leather includes a fibrous base material and a polyurethane foamed resin layer provided on the fibrous base material. The polyurethane foam resin layer contains a plasticizer.

In the present embodiment, the fibrous base material is not particularly limited, and fabrics such as knitted fabrics, woven fabrics, and non-woven fabrics, and natural leather (including floor leather) can be exemplified. Among them, a knitted fabric or a woven fabric is preferable, a knitted fabric is more preferable, and a brushed product of a tricot knitted fabric is particularly preferable from the viewpoint of texture. The fabric is coated or impregnated with a conventionally known solvent-based or solvent-free (including water-based) polymer compound (for example, polyurethane resin or copolymer thereof, and polyvinyl chloride resin), and is dry-coagulated or wet-coagulated. You may use the one which has been made. Further, a known pretreatment agent (for example, a penetrant, a water repellent, a flame retardant, an ultraviolet absorber, etc.) may be applied to the fabric. The fibrous base material may be colored with a dye or a pigment. Further, the surface of the fibrous base material may be raised by a conventionally known raising treatment.

The types of fibers constituting the fibrous base material are not particularly limited, and conventionally known fibers such as natural fibers, regenerated fibers, semi-synthetic fibers, and synthetic fibers can be mentioned, and two or more of these can be combined. May be. Among them, synthetic fibers are preferable, and polyester fibers are more preferable, from the viewpoint of strength and processability.

The synthetic leather according to the present embodiment is formed by laminating a polyurethane foamed resin layer on one surface of the above-mentioned fibrous base material.

In the fibrous base material, the surface on which the polyurethane foam resin layer is laminated is not particularly limited. When the fibrous base material is a brushed product, it is preferably laminated on the brushed surface side from the viewpoint of texture, and laminated on the non-raised surface side from the viewpoint of designability (difficulty of unnatural wrinkles). Is preferable.

In the present embodiment, the polyurethane resin used for the polyurethane foamed resin layer may consist of a polyurethane resin formed by the reaction of the polyol (A) as the main agent and the urethane polyisocyanate prepolymer (B) as the urethane curing agent. preferable. By using the urethane polyisocyanate prepolymer (B), the viscosity can be easily adjusted and the processability is excellent. Here, the urethane polyisocyanate prepolymer (B) is a urethane prepolymer having an isocyanate group at the molecular terminal.

As is well known, polyurethane resin is a general term for polymer compounds having a urethane bond (-NHCOO-), and is generally produced by reacting a polyol with a polyisocyanate (crosslinking / curing reaction). The urethane prepolymer is one in which the reaction between the polyol and the polyisocyanate is stopped at an appropriate place, has a urethane bond in the main chain, and is used as a urethane curing agent when forming a polyurethane resin. There are two types of urethane prepolymers, a urethane polyol prepolymer having a hydroxyl group at the molecular end and a urethane polyisocyanate prepolymer having an isocyanate group at the molecular end, depending on the ratio of the polyol to the polyisocyanate at the time of production. In the polyurethane foamed resin layer of the present embodiment, as described above, it is preferable to select and use the urethane polyisocyanate prepolymer. The isocyanate group present at the molecular end of the urethane polyisocyanate prepolymer reacts with the hydroxyl group of the polyol which is the main agent to form a urethane bond, and a polyurethane resin is formed. In addition, the isocyanate group reacts with the hydroxyl group to generate carbon dioxide. In this way, the polyurethane resin layer becomes a foam layer in which a large number of holes are formed. The isocyanate group of the urethane curing agent remaining after the reaction reacts with the moisture in the atmosphere and cures to complete the reaction.

In the urethane polyisocyanate prepolymer (B), the polyol (B-1) and the polyisocyanate (B-2) are reacted under the condition that the isocyanate group of the polyisocyanate is excessive with the hydroxyl group of the polyol. Can be obtained by

The polyol (B-1) used in producing the urethane polyisocyanate prepolymer is not particularly limited, and for example, polycarbonate polyol, polyester polyol, polyether polyol, acrylic polyol, polyolefin polyol, castor oil polyol, silicon. Modified polyols and the like can be mentioned, and these can be used in combination. Of these, polyester polyols and polyether polyols are preferable from the viewpoint of texture and tactile sensation.

The polyisocyanate (B-2) that can be used in producing the urethane polyisocyanate prepolymer is also not particularly limited, and for example, phenylenediocyanate, tolylene diisocyanate (TDI), and 4,4'-diphenylmethane diisocyanate (MDI). ), 2,4'-Diphenylmethane diisocyanate, naphthalene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate and other aromatic diisocyanates, hexamethylene diisocyanate (HDI), lysine diisocyanate, cyclohexane diisocyanate, isophorone diisocyanate (IPDI), dicyclohexyl. Examples thereof include aliphatic diisocyanates such as methane diisocyanate or alicyclic diisocyanates, and polypeptide MDI containing dimers and trimers of 4,4'-diphenylmethane diisocyanate (MDI). Of these, 4,4'-diphenylmethane diisocyanate (MDI) is preferable from the viewpoint of easy control of the curing reaction, and hexamethylene diisocyanate (HDI) is preferable from the viewpoint of yellowing resistance.

Various conventionally known methods can be adopted for producing the urethane polyisocyanate prepolymer, and the present invention is not particularly limited. For example, a method in which a polyol (B-1) from which water has been removed and a polyisocyanate (B-2) from which water has been removed are mixed at a predetermined ratio and then heated to react in a batch method, or a polyol and poly which have had water removed have been mixed. It is possible to adopt a method in which each of the isocyanates is heated and charged into an extruder at a predetermined ratio to react by a continuous extrusion reaction method.

Examples of the polyol (A) to be reacted with the urethane polyisocyanate prepolymer (B) thus obtained include polycarbonate polyol, polyester polyol, polyether polyol, acrylic polyol, polyolefin polyol, castor oil polyol, silicon-modified polyol and the like. Can be used in combination. Among them, polycarbonate polyol is preferable from the viewpoint of durability (specifically, heat resistance, light resistance, abrasion resistance, abrasion resistance, etc.), and polyester polyol and polyether polyol are preferable from the viewpoint of texture and tactile sensation. ..

The number average molecular weight of the polyol (A) is not particularly limited, but is preferably 90 to 3000. If the number average molecular weight is less than 90, the texture may become coarse and hard. If the number average molecular weight exceeds 3000, the viscosity of the urethane prepolymer composition mixed with the urethane polyisocyanate prepolymer (B) and the plasticizer (C) becomes high, which may affect workability. The number average molecular weight can be measured and determined by a gel permeation chromatography (GPC) method.

The polyurethane foam resin layer of the synthetic leather according to the present embodiment contains a plasticizer (C). By adding a plasticizer, the surface of the obtained polyurethane foamed resin layer is given a tacky feeling, and synthetic leather having a grip suitable for gloves, particularly sports gloves, can be obtained. The plasticizer (C) is preferably added to the polyol (A) from the viewpoint of processability.

In the present embodiment, the plasticizer (C) used for the polyurethane foamed resin layer is not particularly limited, and is, for example, an acrylic plasticizer, a phthalate ester plasticizer, an adipic acid ester plasticizer, and a phosphoric acid. Examples thereof include ester-based plasticizers and trimet acid ester-based plasticizers. Among them, acrylic plasticizers are preferable from the viewpoint of durability (specifically, heat resistance, light resistance, abrasion resistance, abrasion resistance, etc.) and bleed-out suppression, and polyfunctional from the viewpoint of imparting a tack feeling. A hydroxy type acrylic plasticizer is preferable.

The weight average molecular weight of the plasticizer (C) is preferably 1500 to 5500, more preferably 3000 to 4000. When the weight average molecular weight is 1500 or more, durability (specifically, heat resistance, light resistance, abrasion resistance, abrasion resistance, etc.) is improved, and bleed-out of the plasticizer can be prevented. Further, since the volatility is low, problems such as VOC (volatile organic compounds) discharge and odor are improved. When the weight average molecular weight is 5500 or less, it is possible to prevent a decrease in workability because it is possible to suppress an excessive tack feeling. Good workability after liquid preparation. The weight average molecular weight can be measured and determined by a gel permeation chromatography (GPC) method.

The content (dry solid content) of the plasticizer (C) in the polyurethane foamed resin layer is preferably 6 to 14% by mass, more preferably 8 to 11% by mass. When the content of the plasticizer is 6% by mass or more, a tack feeling can be imparted to the surface of the obtained polyurethane foamed resin layer, and the synthetic leather has a grip property. When the content of the plasticizer is 14% by mass or less, bleeding out of the plasticizer can be prevented. Further, since it is possible to prevent the obtained polyurethane resin foam layer from becoming too soft or giving a feeling of tackiness too much, it is possible to prevent deterioration of workability.

In addition to the plasticizer (C), the polyol (A) contains a urethanization catalyst, a cross-linking agent, a silane coupling agent, a filler, and a thixo as long as the physical properties of the polyurethane resin obtained by curing as necessary are not impaired. Granting agent, tackifier, wax, heat stabilizer, light-resistant stabilizer, fluorescent whitening agent, foaming agent, thermoplastic resin, thermosetting resin, dye, pigment, flame retardant, conductivity-imparting agent, antistatic agent, Moisture permeability improver, water repellent, oil repellent, hollow foam, crystalline water-containing compound, water absorbent, hygroscopic agent, deodorant, foam stabilizer, defoaming agent, anti-mold agent, preservative, anti-algae, Any component such as a pigment dispersant, an inert gas, an antiblocking agent, an antioxidant, and a thickener can be used alone or in combination of two or more.

In the present embodiment, the polyurethane foamed resin layer is formed by the reaction of the above-mentioned polyol (A), the above-mentioned urethane polyisocyanate prepolymer (B), and the above-mentioned plasticizer (C). The equivalent ratio of isoacinate group / hydroxyl group when reacting the polyol (A) with the urethane polyisocyanate prepolymer (B) is preferably 1.0 to 2.0, more preferably 1.3 to 1.5. Is. If the equivalent ratio of isoacinate group / hydroxyl group is less than 1.0, unreacted polyol may remain, and the physical properties of the polyurethane resin obtained by curing may be poor or the desired degree of foaming may not be obtained. is there. If the equivalent ratio of isoacinate group / hydroxyl group exceeds 2.0, the curing reaction may proceed too much and the texture and texture may become rough. At this time, the amount of the urethane polyisocyanate prepolymer used as the urethane curing agent with respect to 100 parts by mass of the polyol as the main agent is usually 30 to 90 parts by mass, preferably 40, although it depends on the molecular weight of the main agent and the urethane curing agent. It is ~ 70 parts by mass, more preferably 45 to 55 parts by mass. The isoacinate group / hydroxyl group equivalent ratio referred to here is an equivalent ratio of a mixture of the polyol (A) and the urethane polyisocyanate prepolymer (B).

The thickness of the polyurethane foam resin layer is not particularly limited, but is preferably 100 to 300 μm, and more preferably 150 to 250 μm. When the thickness is 100 μm or more, it prevents the tactile sensation and texture from becoming rough and hard. When the thickness is 300 μm or less, it is possible to prevent the wear resistance from becoming poor.

The method for producing the synthetic leather according to the present embodiment is not particularly limited. For example, as the first manufacturing method
A step of applying a urethane prepolymer composition obtained by mixing a urethane polyisocyanate prepolymer (B), which is a urethane curing agent, and a polyol (A), which is a main agent containing a plasticizer (C), to a fibrous substrate. ,
A step of forming a polyurethane foamed resin layer after attaching a releasable base material to the urethane prepolymer composition, and
The step of peeling off the releasable substrate,
May be included in this order.

Specifically, in the first production method, a urethane prepolymer composition obtained by mixing a urethane polyisocyanate prepolymer (B) which is a urethane curing agent and a polyol (A) which is a main agent containing a plasticizing agent (C). The material is applied to a fibrous base material, and while the urethane prepolymer composition has a viscous state, a releasable base material is attached, and an aging treatment is performed to form a polyurethane foamed resin layer, and then the material is released. The mold base material may be peeled off.

As a second method for producing synthetic leather according to the present embodiment,
A urethane prepolymer composition obtained by mixing a urethane polyisocyanate prepolymer (B), which is a urethane curing agent, and a polyol (A), which is a main agent containing a plasticizer (C), is applied to a releasable substrate. Process,
After adhering the fibrous base material to the urethane prepolymer composition, a step of forming a polyurethane foamed resin layer, and
The step of peeling off the releasable substrate,
May be included in this order.

Specifically, in the second production method, a urethane prepolymer composition obtained by mixing a urethane polyisocyanate prepolymer (B) which is a urethane curing agent and a polyol (A) which is a main agent containing a plasticizing agent (C). A material is applied to a releasable base material, and while the urethane prepolymer composition has a viscous state, a fibrous base material is attached and aged to form a polyurethane foamed resin layer, and then the material is released. The mold base material may be peeled off.

Among them, the second manufacturing method is preferable from the viewpoint of texture. That is, by using the second production method, it is possible to suppress the permeation of the urethane prepolymer composition into the fibrous base material, so that it is possible to prevent the texture of the obtained synthetic leather from becoming coarse and hard.

The releasable base material used in the present embodiment is not particularly limited, and may be a base material having releasability with respect to the polyurethane resin or a base material subjected to a releasable treatment, for example. Examples thereof include a pattern paper, a release-treated cloth, a water-repellent-treated cloth, an olefin sheet or film made of polyethylene resin or polypropylene resin, a fluororesin sheet or film, and a plastic film with a release paper. The releasable base material may have an uneven pattern, and by using such a releasable base material, designability can be imparted to the surface of the synthetic leather.

As a method for applying the urethane prepolymer composition, various conventionally known methods can be adopted and are not particularly limited. For example, a method using a device such as a spray coater, a roll coater, a knife coater, a comma coater or a T-die coater can be mentioned. Of these, coating with a knife coater or a comma coater is preferable in that a uniform thin film layer can be formed.

The coating thickness of the urethane prepolymer composition may be appropriately set according to the desired thickness of the polyurethane foamed resin layer.

After applying the urethane prepolymer composition to the releasable base material (or fibrous base material), heat treatment is preferably performed. Since the curing reaction of the main agent polyol (A) and the urethane curing agent urethane polyisocyanate prepolymer (B) proceeds at room temperature, heat treatment is not always required, but the heat treatment promotes the curing reaction, so that it is produced. In terms of efficiency, it is preferable to perform heat treatment.

Next, while the urethane prepolymer composition (a part of which has undergone a curing reaction to become a polyurethane resin) is viscous, it is bonded to a fibrous base material (or a releasable base material). The polyurethane foam resin layer is formed by aging at room temperature for a certain period of time or aging at a high temperature by heat treatment.

The reaction rate of the polyol (A) as the main agent and the urethane polyisocyanate prepolymer (B) as the urethane curing agent depends on the type and amount of the polyol or prepolymer selected and the additive (particularly urethanization catalyst) used optionally. Since it fluctuates greatly, it is necessary to appropriately set the aging treatment conditions depending on the selected conditions, but it is usually carried out at room temperature for about 1 day to 1 week. In this process, the curing reaction between the polyol (A), which is the main agent, and the urethane polyisocyanate prepolymer (B), which is the urethane curing agent, is completed. If the curing reaction is incomplete, there is a risk that physical properties such as wear resistance will be poor.
After curing, the releasable base material can be peeled off to obtain the synthetic leather of the present embodiment.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples.

The evaluation items were as follows.

[Tactile (grip)]
The tactile sensation of the test piece was sensory evaluated and judged according to the following evaluation criteria.
(Evaluation criteria)
Grade 5: Very soft and has a strong tack feeling.
Grade 4: Soft and tacky touch.
Grade 3: Soft but tacky to the touch.
Level 2: A tactile sensation that is slightly lacking in softness and slightly lacking in tackiness.
Grade 1: Hard and non-tacky to the touch.

[Example 1]
[Fibrous base material]
Polyester tricot brushed fabric ( ^{grain: 87 g / m 2} , back yarn: 22 dtex / 1f polyester monofilament yarn, 1-0 / 1-2, front yarn: 56 dtex / 48f polyester multifilament yarn, 1-0 / 3-4) It was used as a fibrous base material.

調製方法：製造例１に従い、各原料をミキサーにて撹拌し、ポリオール液（Ａ）を得た。

Preparation method: According to Production Example 1, each raw material was stirred with a mixer to obtain a polyol solution (A).

調製方法：製造例２に従い、６０℃に保温した１リットルの４ツ口フラスコに、ポリオールを入れて撹拌した後、イソシアネート系硬化剤を添加し、水酸基がなくなるまで８０℃にて撹拌し、ウレタンポリイソシアネートプレポリマー（Ｂ）を得た。

Preparation method: According to Production Example 2, a polyol is placed in a 1-liter 4-necked flask kept at 60 ° C. and stirred, then an isocyanate-based curing agent is added, and the mixture is stirred at 80 ° C. until the hydroxyl groups disappear, and urethane is used. A polyisocyanate prepolymer (B) was obtained.

調製方法：処方１に従い、製造例１のポリオール液（Ａ）にアクリル系可塑剤、カーボンブラック顔料を添加し撹拌した後に、製造例２のウレタンポリイソシアネートプレポリマー（Ｂ）を添加し撹拌した後、直ちに、塗布操作に供する。

Preparation method: According to Formulation 1, an acrylic plasticizer and a carbon black pigment were added to the polyol solution (A) of Production Example 1 and stirred, and then the urethane polyisocyanate prepolymer (B) of Production Example 2 was added and stirred. , Immediately ready for coating operation.

That is, the urethane prepolymer composition prepared according to Formulation 1 was applied on a paper pattern in the form of a sheet with a comma coater so as to have a thickness of 100 μm. After heating the sheet with a heat setter at 95 ° C. for 7 minutes, the urethane prepolymer composition is attached to the non-raised surface of the fibrous substrate while the urethane prepolymer composition has viscosity, and the clearance is 0. It was pressed to 65 mm and heat-aged at 130 ° C. for 10 minutes. Then, the release paper was peeled off to obtain synthetic leather.

[Examples 2 to 6, Comparative Example 1]
Synthetic leather was obtained in the same manner as in Example 1 except that the formulations of the polyurethane foam resin layer were the formulations 2 to 7 in Table 4.

[Example 7]
A synthetic leather was obtained in the same manner as in Example 1 except that a polyurethane resin foam layer was attached to the raised surface side of the fibrous base material.

The results are shown in Table 4, and Examples 1, 3, 4, and 7 had a tactile sensation (grip property) of grade 4, and were suitable for synthetic leather for gloves. Among them, Examples 1 and 7 had the best softness and tackiness, and had a grip property suitable for use in sports gloves. In Example 7, since the polyurethane foamed resin layer was laminated on the raised surface of the fibrous base material, the texture was superior to that of Example 1.
Examples 2 and 6 have a second-grade evaluation of tactile sensation (grip property), and although they are suitable as synthetic leather for gloves, they are slightly too soft and slightly tacky as compared with Examples 1, 3, 4, and 7. It was missing.
Example 5 has a tactile sensation (grip property) of 5th grade, and although it is suitable as synthetic leather for gloves, it is considerably softer and has a stronger tack feeling than Examples 1, 3, 4, and 7. there were.
In Comparative Example 1, the evaluation of the tactile sensation (grip property) was first grade, it was coarse and hard, and it lacked the tacky feeling.

Claims (4)

A synthetic leather obtained by laminating a polyurethane foamed resin layer on a fibrous base material, wherein the polyurethane foamed resin layer contains a plasticizer. The synthetic leather according to claim 1, wherein the plasticizer is an acrylic plasticizer. The synthetic leather according to claim 1 or 2, wherein the content (dry solid content) of the plasticizer in the polyurethane foamed resin layer is 6 to 14% by mass. The synthetic leather according to any one of claims 1 to 3, wherein the thickness of the polyurethane foam resin layer is 100 to 300 μm.