JPH0379380B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a method for producing a highly wear-resistant and flexible sheet material. (Prior Art) The market for sheet-like materials in which polyurethane is added to fiber sheets is expanding extremely widely, with sheet-like materials replacing leather being a typical example. There are various requirements for such sheet-like materials. A typical example is that it has high abrasion resistance and high durability. Although such a request is a very basic request,
Because this is an extremely difficult request, it has been viewed as impossible to solve from the beginning, and currently not much has been done about it. (Problems to be Solved by the Invention) In view of the above-mentioned circumstances, the present invention seeks to solve the following problems, which were practically not subject to consideration in the past. (1) The nap is very prone to shedding, especially in soft suede substitutes. (2) The naps are highly susceptible to shedding, especially in suede substitutes with dense naps. (3) In fur substitutes that have long naps, the long naps are very likely to fall off. (4) Fibers ooze out in a snagging pattern, especially in sheets based on nonwoven fabrics made of long fibers. (5) Pilling occurs especially in sheets made of short fibers. (Means for Solving the Problem) As a result of intensive study, the present inventors have solved the problem that was thought to be difficult to achieve in the past by adopting a special polyurethane and a special coagulation method. The purpose has been achieved and the present invention has been achieved. In order to achieve this object, the present invention has the following configuration. That is, after applying a polyurethane solution in which the polymeric diol component is mainly polyether, the chain extender is diamine, and the nitrogen content is 3.5% or less to the fiber entangled sheet, at least 1% or more water-soluble high This is a method for producing a wear-resistant sheet material characterized by wet coagulation in an aqueous bath in which molecules are dissolved. The present invention will be explained in more detail below. The polymeric diol that is a component of the polyurethane elastomer of the present invention has hydroxyl groups at both ends,
It is mainly composed of polyether with a molecular weight of 800 or more, preferably 1,500 to 4,000. And particularly preferred is 2500-4000. When the molecular weight is in the range of 2,500 to 4,000, the sheet exhibits flexibility while having abrasion resistance.
Particularly preferred. Particularly preferred polyether-based polymer diols include poly(ethylene oxide) glycol, poly(propylene oxide) glycol, poly(tetramethylene oxide) glycol, and mixtures thereof. The polyurethane of the present invention is mainly composed of such polyether-based components, but it goes without saying that polyester-based polymer diol components can also be used. Particularly preferred are polyethylene adipate, polypropylene adipate, polytetramethylene adipate, polyhexamethylene adipate, polycaprolactone glycol, polycarbonate diol, and the like. The diisocyanate is not particularly limited, and conventionally known diisocyanates can be used. Preferred diisocyanates include phenylene diisocyanate, toluylene diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenyldimethylmethane-4,4'-diisocyanate, naphthylene diisocyanate, diphenyl diisocyanate, ethylene diisocyanate, tetramethylene diisocyanate, and hexane diisocyanate. Organic diisocyanates consisting of methylene diisocyanate, lysine diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, dicyclohexyldimethylmethane-4,4'-diisocyanate, xylylene diisocyanate, etc., and mixtures thereof;
Furthermore, reaction products of these organic diisocyanates with polyhydroxy compounds, isocyanate group-containing polyisocyanates obtained by trimerization of organic diisocyanates, or biurets such as those obtained by the method of German Patent Specification No. 1101394. group-containing polyisocyanate, etc. More preferred are aromatic organic diisocyanates and alicyclic organic diisocyanates. Particularly preferred from the viewpoint of sheet material strength, rebound, and stain resistance are toluylene diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenyldimethylmethane-4,4'-diisocyanate, naphthylene diisocyanate, and dicyclohexylmethane-4. , 4'-diisocyanate, dicyclohexyldimethylmethane-4,4'-diisocyanate or mixtures thereof. The chain extender is a diamine. Typical examples are P-phenylenediamine, m-phenylenediamine, tolylenediamine, naphthylenediamine,
4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl thioether, 4,4'-diaminodiphenyl sulfone, 4,4'-diamino-3,3 '-dimethyldiphenylmethane, 4,4'-diamino-3,
Aromatic organic diamines such as 3'-diclodiphenylmethane, 4,4'-diaminodiphenylmethylmethane, ethylenediamine, propylene diamine, menthanediamine, isophorone diamine, cyclohexylene diamine, 4,4'-diaminodicyclohexylmethane, 4 , 4'-diamino-3,3'-dimethyldicyclohexylmethane, aliphatic organic diamines such as xylylene diamine, hydrazine, foamy hydrazine, carbodihydrazide, organic dicarboxylic acid dihydrazide (e.g. adivic acid, sebacic acid, terephthalic acid) , dihydrazides such as isophthalic acid), disemicarbazides and thiosemicarbazides, aminocarboxylic acid hydrazides such as aminoacetic acid hydrazide, α-aminopropionic acid hydrazide, P-aminobenzoic acid hydrazide, etc., or mixtures thereof. Aromatic organic diamines or alicyclic organic diamines are preferred, among which 4,4'-diaminodiphenylmethane, tolylene diamine, 4,4'-diaminodicyclohexylmethane, 4,4'-diamino-3,3' -dimethyldicyclohexylmethane is preferred. In the present invention, the polymer diol is mainly polyether and the chain lengthening agent is diamine for the following reason. In other words, it is already known to produce a polyurethane elastomer consisting of a polymeric diol, an organic polyisocyanate, and a glycol chain extender, and to impregnate and/or coat a fiber sheet with the polyurethane, and it has been put into practical use in some artificial leathers. has been transformed into
However, composite sheets made from such conventional glycol-based polyurethane elastomers tend to have a hard texture and lack flexibility, and also tend to lose their shape and harden their texture when worn or used as secondary products. This is because the object of the present invention could not be achieved. In the present invention, the nitrogen content (hereinafter abbreviated as N%) in the polyurethane is 3.5% or less. Therefore, when polymerizing polyurethane, the polymer diol, diisocyanate, and chain extender are appropriately adjusted. If it exceeds 3.5%, the resulting sheet will have a hard feel and the abrasion resistance will not improve. On the other hand, if the N% is too low, the heat resistance of the sheet often decreases. Therefore, N% is 0.9
% or more is preferable. When applying the polyurethane having such a composition to the fiber sheet, it is applied in the form of a solution. If it is a dispersion liquid such as an emulsion, even if it is wet-coagulated under similar conditions, it cannot have strong abrasion resistance and be flexible. The fiber entangled sheet used in the present invention is not particularly limited, and conventionally known fiber entangled sheets can be applied. In particular, the effects of the present invention are particularly great on materials having raised naps on the surface, such as so-called suede-like leather substitutes and fur substitutes. There are various types of such fiber-entangled sheets, such as needle-punched sheets, double-woven fabrics, and tricot sheets, but when the manufacturing method of the present invention is applied to these sheets, very favorable effects (the naps do not fall off,
The texture is soft. It goes without saying that the present invention is not limited to these fiber entangled sheets. Furthermore, the constituent fibers of the fiber sheet used in the present invention are not particularly limited. Various fibers can be used, such as ultrafine fibers and fibers with tapered ends. In the present invention, the polyurethane solution is applied to the fiber-entangled sheet, and the method of applying the polyurethane solution is not particularly limited, and the polyurethane solution is applied to the sheet by a general impregnation method, spraying, coating, etc. Granted. The amount applied varies depending on the type of sheet, density, etc., and cannot be generalized, but it is 1.5 to 150% by weight of the fibers that make up the sheet.
It is desirable from the viewpoint of product texture, physical properties, etc. It goes without saying that various stabilizers, coagulation regulators, etc. may be added to the polyurethane solution. Thereafter, it is wet-coagulated in an aqueous bath containing at least 1% or more of a water-soluble polymer. The proportion of water in the coagulation system shall be at least 30% or more, and the coagulation system shall be a homogeneous phase. Particularly preferred examples of typical water-soluble polymers include polyvinyl alcohol, polyvinyl acetate, and copolymers thereof, starch, carboxymethyl cellulose, polyacrylic acid, polyethylene glycol, and copolymers thereof. . The proportion of the water-soluble polymer in the coagulation system varies widely depending on its viscosity, molecular weight, and affinity with water, but is at least 1%, preferably 3% or more. However, if there are too many, the cost will increase.
The content is preferably 20% or less, since this causes disadvantages such as time required for coagulation and time required for removal of water-soluble polymers. The solidification temperature is not particularly limited, but is 31
It is preferable to carry out the reaction at a temperature of ±30°C. If the temperature exceeds 61°C, the sheet often deforms during solidification, so care must be taken. Also, if the temperature is 0°C, it is difficult to control the temperature. [Action of the Invention] It is unclear why the effects of the present invention are exhibited when a specific polyurethane is wet-coagulated in a water-soluble polymer-containing system. However, it has been found that by adopting the structure of the present invention, fibers and polyurethane are bonded more firmly than in conventional wet coagulation. On the other hand, the adhesion seems to be slightly weaker than that of conventional dry coagulation.
However, the mechanism behind this formation is unknown. [Example] A more detailed explanation will be given below with reference to Examples. Note that the following abbreviations are used in the examples. Abbreviation Chemical name PTHF
Poly(tetramethylene oxide) glycol PCL Polycaprolactone glycol PEA Polyethylene adipate glycol MDI
Diphenylmethane-4,4'-diisocyanate MBA 4,4'-diaminodiphenylmethane EG Ethylene glycol Measurements in the Examples were carried out by the following method. (1) Method for measuring strength The measuring method in the present invention was as follows. 2cm sample at 20℃±2℃, RH65%±2%
Cut the specimen to a width of 10 cm, and pull it at a speed of 10 cm/min. Strength is the quotient of the maximum stress during a tensile test divided by the width of the sample. Moreover, the elongation was defined as the elongation at the time of maximum stress during the tensile test. (2) Flexibility measurement method: Measured using the cantilever test method in JIS L 1079 Chemical Fiber Fabric Test Method. (3) Abrasion resistance measurement method (Seafar abrasion test) Used to evaluate the abrasion resistance of suede-like leather substitutes. The wear element was a nylon brush, the load was 8 pounds, the number of revolutions per minute was 60, and the number of times the brush broke was defined as the wear resistance. (4) The flocking strength was determined according to JIS-L1084-1977 flocking strength method A (friction tester method) A-2 (edge method) until the flocking pile came off and the base fabric was exposed. The number of frictions was measured and indicated according to the following criteria. 5th grade is 3000 times or more, 4th grade is 2000 or more but less than 3000 times, 3rd grade is 1000 or more but less than 2000 times, 2nd grade is 2000 times or more but less than 2000 times.
500 times or more but less than 1000 times, 1st grade is less than 500 times. Example 1 Polyethylene terephthalate 50 as island component
50 parts of polystyrene as a sea component,
16 islands/filament stretched 2 or 3 times, thickness 3.4 denier, length 51 mm, number of crimps
Using 15/inch polymer array fiber, card,
A nonwoven fabric with an apparent density of 0.170 g/cm ³ was obtained through the steps of cross lapping and needle punching. The nonwoven fabric was impregnated with a 20% aqueous solution of polyvinyl alcohol, dried, and then immersed in perchloroethylene to dissolve the polystyrene to obtain a nonwoven fabric in which bundles of ultrafine fibers were entangled. Next, PTHF with a molecular weight of about 3000 and a molecular weight of about
3000 PCL were mixed so that the former was 75% and the latter was 25%, and then 2 molar equivalents of MDI were added to the polymer diol and reacted to obtain a prepolymer. The prepolymer is then dissolved in DMF,
Polyurethane with a 25% solution viscosity of 400 poise was obtained by chain elongation with MBA. The N% of this polyurethane is approximately 2.3%. This polyurethane was diluted to 13% with DMF and impregnated into the nonwoven fabric. The amount of polyurethane applied is calculated as follows:
It was 45 parts to fiber. Next, it was wet-coagulated for 2 hours in a 10% aqueous solution of polyvinyl alcohol, the water temperature was raised to 80°C, the solvent and polyvinyl alcohol were removed, and it was dried. The resulting sheet was sliced to a thickness of 1.1 mm, and the surface was buffed with sandpaper. The thickness of the sheet after buffing was 0.85 mm. The sheet is dyed with Kayalon Polyester Gray in a high-temperature, high-pressure jet dyeing machine.
Using NG (disperse dye) 2% o, w, f dye solution,
Staining was carried out at 125°C for 1 hour. The obtained sheet was brushed to obtain a suede-like sheet with an apparent density of 0.25 g/cm ² . Table 1 shows the physical property data of this product. Although it is flexible, it is found to be extremely abrasion resistant. Figure 1 shows a cross-sectional photograph of this product. It can be seen that the fibers and polyurethane adhere well despite being wet coagulated. Comparative Example 1 PEA with a molecular weight of about 2000 was reacted with MDI,
A prepolymer was prepared, then dissolved in DMF, and chain-extended with EG to produce a polyurethane with an N% of approximately 4%. This polyurethane was applied to the sheet made of ultrafine fibers of Example 1. The amount of polyurethane applied is calculated as follows:
It was 50 parts per fiber. Next, it was wet-coagulated in water for 2 hours and treated in the same manner as in Example 1 to obtain a raised sheet. Table 1 shows the physical property data of this product. Although it has a hard texture, it is clear that it is not abrasion resistant. Comparative example 2 PTHF and PCL with a molecular weight of about 1500, the former being 75%,
The latter was mixed to 25%, and then reacted with MDI to obtain a prepolymer, which was further chain-extended with MBA to obtain a polyurethane with a 25% solution having a viscosity of 300 poise. The N% of this polyurethane is about 3.8%. This polyurethane is applied to the sheet made of ultrafine fibers of Example 1, and then treated in the same manner as in Example 1,
A napped sheet was obtained. Table 1 shows the physical property data of this product. It can be seen that although it is hard, it has low wear resistance. Figure 2 shows a cross-sectional photograph of this product. It can be seen that the fibers and polyurethane are in conventional wet coagulated form.

[Table] Example 2 A polybutylene terephthalate fiber (containing 0.1% titanium oxide) with 25 denier, 45 mm length, non-densified and sharpened at both ends, manufactured according to the method described in JP-A No. 54-38922 ( Here, the denier is the value before sharpening, and corresponds to the value at the center of the fiber).
100 g/m ² ), a fibrous layer was formed at a density of about 800 g/m ² . Use FPD-1 type #36 needle manufactured by Organ Needle Co., Ltd. as a felting needle with a needle depth of 10 mm.
Needle punching was performed under conditions of a punching number of 300 punches/cm ² . After cutting off the excessively long fluff that penetrated the back surface, the polyurethane of Example 1 was applied,
Wet coagulation was carried out for 2 hours in water in which 7% PVA was dissolved. After air drying, most of the short fibers were raised on the surface using a hand card, and excess fibers were removed. Furthermore, brushing helped to even out the erect hair. The resulting raised structure has fibers with sharpened tips raised in good parallelism, average length of raised hair of 30 mm, appearance similar to mink prickly fur, and very good surface touch. In the structure, about 1 to 30 short fibers (about 10 on average) are implanted by penetrating the base fabric almost vertically, and each short fiber is implanted in a V-shape at one location. The flocking is done in a mixed state, with some flocking through the back, some penetrating into the base fabric. These relatively thick denier napped short fibers are individually flocked perpendicularly to the base fabric and do not directly affect the bending of the structure.
It had an extremely flexible texture. In addition, the flocking strength of the raised hair was very strong at grade 5. Comparative Example 3 Comparative Example 3 was the same as Example 2, except that the coagulation bath was only water. The texture was the same as in Example 2, but the surface was slightly prone to cracking due to bending, which was slightly worse than in Example 1, and the flocking strength of the raised pile was 3 to 3.
It was grade 4, which is a little weak. [Effects of the Invention] The effects of the present invention are summarized as follows. (1) Flexible and durable sheets can be easily made. (2) Particularly in soft suede substitutes, naps were very likely to fall off in the past, but when the method of the present invention was applied, the falling off of naps, etc. was greatly reduced. (3) The durability of fur with long naps and fur substitutes (non-shedding of naps) has been greatly improved. (4) In particular, the anti-snagging properties of sheets based on nonwoven fabrics using long fibers have been greatly improved. (5) Since the surface of the sheet became less susceptible to change over time, the change over time during practical use of the sheet was significantly reduced. (6) Since it is extremely easy to make, it can be made at low cost and in good quality.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional photograph showing the cross-sectional shape of the fibers of the abrasion-resistant sheet material of Example 1 according to the present invention, magnified approximately 200 times. FIG. 2 is a cross-sectional photograph showing the cross-sectional shape of the fibers of the sheet-like material of Comparative Example 2, magnified approximately 200 times.

Claims (1)

[Claims] 1 The polymeric diol component is mainly polyether, the chain extender is diamine, and the nitrogen content is
Production of a wear-resistant sheet product characterized by applying a polyurethane solution prepared to a concentration of 3.5% or less to a fiber-entangled sheet and then wet-coagulating it in an aqueous bath in which at least 1% or more of a water-soluble polymer is dissolved. Method.