JPH0470403B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a method for manufacturing work gloves made of fabric coated with urethane resin, which have flexibility and excellent solvent resistance. [Prior Art] Conventional work gloves are made by covering the entire surface of a glove base made by knitting or sewing knitted cloth with natural rubber, synthetic rubber, vinyl chloride resin, etc. is the mainstream. However, gloves coated with natural rubber or synthetic rubber have insufficient solvent resistance. Gloves coated with vinyl chloride resin are generally made by dipping a glove base made of cloth into a vinyl chloride plastisol. The smell of stabilizers remains, oil resistance and solvent resistance are poor, and the inside of the glove gets stuffy during work due to poor breathability. There are problems such as the film is thick, hard, and has poor elasticity and flexibility. Some solvent-resistant work gloves are coated with a solvent-based urethane resin solution, but since solvents are used in the manufacturing process, they are undesirable for the working environment and pose a risk of fire and explosion. However, there are problems in terms of cost and safety, such as the need for explosion-proof equipment and solvent recovery equipment in production equipment. Furthermore, since the fabric is soaked in the urethane resin solution, the resulting gloves are extremely hard and have poor workability. Although this is not a common method, work gloves have also been produced in which a fabric glove base is coated with a polyurethane emulsion. However, the polyurethane emulsion penetrates into the fabric, so to prevent this, it is necessary to immerse the glove base in metal salt, etc., then apply the polyurethane emulsion to the surface, dry it, and then wash off the metal salt. , is extremely time-consuming and costly. In addition, in order to prevent this polyurethane emulsion from penetrating, a foaming agent was added to the polyurethane emulsion to create a mechanically foamed polyurethane emulsion, and this was applied to the surface of the glove base. Polyurethane-coated gloves have also been manufactured by coating the first layer with a non-foamed polyurethane emulsion, but the mechanical properties of the first foamed layer are poor and the two-coating method is costly. There is a problem with getting high. Another way to prevent penetration when using polyurethane emulsion is to increase the viscosity by adding a thickener to the polyurethane emulsion.This method can prevent penetration to some extent, but it requires thinner wall thickness. It is difficult to do so. When the wall thickness increases, problems such as air bubbles are more likely to occur and cracks are more likely to occur on the glove skin. The cause of the crack is a problem common to all gloves coated with emulsion-based materials, but since the applied polyurethane emulsion hardens from the epidermis (outside), there is no place for moisture inside the epidermis to escape. It is believed that a crack will occur. [Means for Solving the Problems] As a result of extensive studies by the present inventors in order to eliminate the drawbacks of conventional work gloves as described above, the present inventors have developed gloves that are heated by a hand pattern at a specific temperature. By applying a specific polyurethane resin emulsion with heat-sensitive gelling properties to the substrate and drying it,
The inventors have discovered that it is possible to obtain work gloves that are light, thin, stretchable and flexible, and have excellent solvent resistance, oil resistance, etc., and have thus arrived at the present invention. That is, in the present invention, after inserting a cloth glove base into a heated hand mold, a urethane resin emulsion having heat-sensitive gelling properties is applied to the surface of the glove base, and then dried to produce work gloves. The urethane resin emulsion is obtained by reacting a polyisocyanate with a compound having a molecular weight of 200 to 10,000 having two or more active hydrogen atoms at a molar ratio of NCO groups/active hydrogen atoms of 1.02 to 1.2. Free isocyanate group content is 0.2 to 1.5% (weight%, hereinafter the same) and oxyethylene chain content is 5%.
~20% of the urethane polymer and a nonionic surfactant with an HLB of 6 to 18 to the urethane polymer.
It has heat-sensitive gelling properties obtained by chain extension with a polyamine compound containing two or more primary and/or secondary amino groups in one molecule in the presence of ~15% water. The present invention relates to a method for manufacturing work gloves characterized by using a nonionic urethane resin emulsion. [Example] The nonionic urethane resin emulsion used in the present invention is also described in Japanese Patent Application No. 174376/1982. In order to prepare the urethane resin emulsion, first, a polyisocyanate and a compound having a molecular weight of 200 to 10,000 and having two or more active hydrogen atoms are combined.
NCO/active hydrogen atom is 1.02/1 to 1.2/1 in mole
A urethane polymer with a free isocyanate group content of 0.2-1.5% and an oxyethylene chain content of 5-20% is prepared. Specific examples of the polyisocyanates include all aromatic, aliphatic or alicyclic polyisocyanates such as dicyclohexylmethane diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate, xylylene diisocyanate, naphthalene diisocyanate, hexamethylene diisocyanate, and isophorone diisocyanate. Examples include polyisocyanates and dimers and trimers thereof. All of the above polyisocyanates are preferable, but for example, if non-yellowing gloves are required, it is preferable to use aliphatic or alicyclic isocyanates. If necessary, aromatic isocyanates may be used. These polyisocyanates may be used alone or in combination of two or more. Molecular weight 200 to 10,000, preferably 200, having the above 2 or more, preferably 5 or less active hydrogen atoms
~3000 compounds include two or more hydroxyl groups, carboxyl groups, or amino groups at the end or in the molecule (in the case of primary, it is calculated as one active hydrogen),
Contains a group having an active hydrogen atom such as a mercapto group. Specific examples include polyether, polyester, polyether ester, polythioether, polyacetal, polybutadiene, etc., but polyoxyethylene glycol, polyoxytetra Methylene glycol, polyoxyalkylene glycol with a molecular weight of 1000 to 3000 such as polyoxyethylene oxypropylene random copolymer, polybutylene adipate diol, polyethylene adipate diol, polyester of 3-methyl-1,5-pentanediol and adipic acid , molecular weight of polyester of β-methyl-δ-valerolactone and adipic acid, etc.
1000-2000 polyadipate diols are particularly useful. A molecular weight having two or more such active hydrogen atoms.
200 to 10,000 compounds may be used alone or in combination of two or more types, but since it is necessary that the urethane polymer produced using them contains 5 to 20% of oxyethylene chains, It is necessary to appropriately select or use them in combination so as to satisfy these ranges. The molecular weight of the compound having an active hydrogen atom is
When it is less than 200, the hard segment portion increases, making it impossible to produce a urethane resin emulsion that provides a flexible film with excellent tensile strength. Also
If it exceeds 10,000, the soft segment portion increases, making it impossible to produce a urethane resin emulsion that is flexible but provides a film with excellent tensile strength and excellent solvent resistance. The reaction between these compounds having a molecular weight of 200 to 10,000 and having two or more active hydrogen atoms and polyisocyanate is carried out at a temperature of 50 to 120°C by a conventionally known single-stage or multi-stage isocyanate polyaddition reaction method. It will be held in In this case, if necessary, a low molecular weight chain extender having two or more active hydrogen atoms, a reaction control agent such as phosphoric acid, benzoic acid, p-toluenesulfonic acid, adipic acid, dibutyltin dilaurate, stannous octoate, etc. , triethylamine, triethylenediamine, and an organic solvent that does not react with isocyanate groups may be added at a necessary stage such as during the reaction stage or after the reaction is completed. Specific examples of the low molecular weight chain extender having 2 or more (preferably 5 or less) active hydrogen atoms include 1,4-butanediol, trimethylolpropane, 3-methyl-1,5-pentanediol. , neopentyl glycol, hexanediol, propylene glycol, ethylene glycol, diethylene glycol, and other polyhydric alcohols. Specific examples of the organic solvent include acetone, methyl ethyl ketone, tetrahydrofuran, dioxane, dimethylformamide, ethyl acetate, toluene, xylene, methylene chloride, and the like. When manufacturing urethane polymers, NCO/
Active hydrogen atoms have a molar ratio of 1.02 to 1.2, preferably
It is necessary to set the free isocyanate group content to 1.05 to 1.15, and the content of free isocyanate groups in the resulting urethane polymer is preferably 0.2 to 1.5%. When the NCO/active hydrogen atom molar ratio exceeds 1.2 or the free isocyanate group content exceeds 1.5%, the emulsion stability and aging stability of the nonionic urethane resin emulsion obtained by chain extension with the polyamine compound described below Sexuality becomes poor,
If the molar ratio of NCO/active hydrogen atoms is less than 1.02 or the content of free isocyanate groups is less than 0.2%, a large amount of organic solvent will be required to increase the viscosity, resulting in poor economic efficiency. In some cases, the polymer has a high molecular weight and is highly crosslinked, making it difficult to emulsify and disperse it uniformly. Furthermore, the urethane polymer obtained is 5 to 20%
oxyethylene chains. If the oxyethylene chain content in the urethane polymer is less than 5%, the hydrophobicity of the urethane polymer skeleton becomes too strong, making uniform emulsion dispersion impossible.If it exceeds 20%, emulsion dispersibility becomes good, but the formation A urethane resin emulsion agent that can produce work gloves that have excellent emulsion stability and improved water resistance, hot water resistance, solvent resistance, etc., since the physical properties of films formed from materials, especially water resistance, are significantly deteriorated. I won't be able to do it. In the present invention, 2 to 15% of HLB6 to 18 is added to the urethane polymer thus prepared.
Heat-sensitive gelling property obtained by reacting a polyamine compound containing two or more primary and/or secondary amino groups in one molecule as a chain extender in the presence of a nonionic surfactant and water. A nonionic urethane resin emulsion is prepared. Specific examples of nonionic surfactants with HLB 6 to 18 used when emulsifying and dispersing urethane polymers while chain elongating include alkyl esters, higher alcohols, alkyl phenols,
Examples include styrenated phenols, aliphatic amines, and ethylene oxide adducts such as sorbitan alkyl esters. These may be used alone or in combination of two or more, but a mixture having an HLB of 8 to 17 is preferred. The amount of the surfactant used is 2 to 15% based on the urethane polymer, but if the amount is less than 2%, uniform emulsification and dispersion will not be possible, and if it exceeds 15%, the emulsion and dispersion will not be good. However, the water resistance of the formed film decreases. Specific examples of polyamine compounds containing two or more primary and/or secondary amino groups in one molecule used as chain extenders include ethylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, Examples include pepyrazine, hydrazine, tolylene diamine, and xylylene diamine. The amount of the polyamine compound used is usually an amount containing 0.5 to 1.5 equivalents of amino groups, preferably 0.7 to 1.2 equivalents, per equivalent of free isocyanate groups in the urethane polymer. If the amount of amino groups per equivalent of the free isocyanate group is less than 0.5 equivalents, chain elongation will be insufficient and terminal termination will occur with water, making emulsification difficult and reducing the performance of the urethane resin emulsion. In addition, if it exceeds 1.5 equivalents,
Since the polyamine causes terminal termination, the chain is not elongated, which causes a decrease in the performance of the urethane resin emulsion. The nonionic urethane resin emulsion with heat-sensitive gelling properties used in the present invention obtained in this way has an average particle diameter of 0.1 to 2 μm and a solid content of 40 to 40 μm.
Preferably it is 60%. In addition, heat-sensitive gelling property as referred to in this specification is due to the cloud point phenomenon of the nonionic activator, which causes the emulsified dispersion of the urethane resin emulsion to become unstable when the temperature exceeds a certain level, and when the temperature rises further, the urethane resin rapidly deteriorates. A phenomenon in which an emulsion is destroyed and turns into a gel. To the urethane resin emulsion, a metal salt used as a coagulant for natural rubber latex or synthetic rubber latex may be appropriately added in order to adjust the gelation rate. Specific examples of metal salts include calcium nitrate, ammonium sulfate, calcium chloride, aluminum sulfate, and the like. These may be used alone or in combination of two or more. Furthermore, if necessary, pigments, thickeners, ultraviolet inhibitors, antioxidants, inorganic fillers, flame retardants, conductive materials, anti-slip materials, etc. may be added to the urethane resin emulsion. In the present invention, after the glove base is inserted into a heated hand mold, the urethane resin emulsion having heat-sensitive gelling properties is applied thereto. The fabric glove base used in the present invention is not particularly limited, and any material that is commonly used as a work glove base can be used. The glove base may be knitted or sewn. A specific example thereof is one made of knitted cloth. In particular, glove bases made of unbleached cotton knitted fabric (unbleached cotton knitted fabric is water repellent because it has oil and fat attached to it) and glove bases made of water-repellent treated cotton knitted fabric prevent the penetration of urethane resin emulsion. This is preferable because it has the effect of Furthermore, the cotton knitted fabric is knitted using knitting yarn with a count of #30 to #40, which prevents the penetration of the urethane resin emulsion and makes it light, thin, and stretchable for use as work gloves. This is preferable because it provides gloves with excellent flexibility and flexibility. The hand shape is not particularly limited as long as it can heat the glove base, and for example, hand shapes made of aluminum, ceramics, earthenware, Teflon-treated metal, etc. can be preferably used. The hand mold is heated, for example, to 50 to 120°C, preferably 50 to 80°C, in order to gel the urethane resin emulsion. If the temperature is less than 50°C, the emulsion will not gel sufficiently, and the gloves obtained by penetrating the urethane resin emulsion into the fabric will become hard, have reduced flexibility, and tend to have poor workability. In addition, when the temperature exceeds 120℃, gelation occurs rapidly and the emulsion loses its fluidity, so the thickness of the urethane resin that adheres to the glove base becomes uneven, and bubbles, cracks, and rips occur, resulting in smooth urethane resin. It becomes difficult to form a film. There are no particular limitations on the method of applying the urethane resin emulsion to the glove base inserted into the heated hand mold, but methods include dipping, flow coating, and coating the glove base inserted into the heated hand mold using the liquid surface of the urethane resin emulsion. A method of applying pressureless coating while rotating a mold may be adopted. The urethane resin emulsion quickly gels when attached to the glove base, does not penetrate into the interior of the fabric, and forms a uniform wet film on the surface. Note that "not penetrating into the inside of the fabric" means that when the obtained work gloves are turned inside out and observed, urethane resin is not observed on the back side. The thickness of the film can be easily adjusted by simply adjusting the coating time and the viscosity of the emulsion. For example, a thickener (Superflex VR manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added while stirring the urethane resin emulsion described in Example 1, which will be described later.
A glove base (fabric weight: 35.5 g/pair) manufactured by sewing cotton stockinette cloth knitted from cotton stockinette knitting yarn of count #30 to #40 on the surface of a solution prepared in a manner that does not generate air bubbles. Table 1 shows the relationship between viscosity and film thickness when coating is carried out by inserting a mold into the mold and rotating the mold.

[Table] **: Thickness of the glove after drying the wet film The wet film thus formed is dried to produce the intended work glove. There are no particular limitations on the drying method and drying conditions, for example, 85-150°C, more preferably 90-150°C.
Heat treatment may be performed for 5 to 60 minutes in a hot air drying oven at 110°C. Next, the manufacturing method of the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples. Example 1 Polybutylene adipate diol (average molecular weight
1000) 180 parts, polyoxyethylene oxypropylene random copolymerized glycol (average molecular weight
3400, oxyethylene chain content 80%) 20 parts, 1,
79.9 parts of dicyclohexylmethane diisocyanate was added to a mixture consisting of 3.8 parts of 4-butanediol, 3.8 parts of trimethylolpropane, and 143.8 parts of methyl ethyl ketone, and the mixture was reacted at 75°C for 90 minutes to form a urethane polymer (oxyethylene chain) with a free isocyanate group content of 1.03%. A methyl ethyl ketone solution with a content of 5.56% was obtained. To the resulting solution, 14.4 parts of polyoxyethylene aryl phenol ether type nonionic surfactant (HLB = 15) (nonionic surfactant blending ratio 4.77%), which is an ethylene oxide adduct of distyrenated phenol, was added and mixed. After that, water
Add 301.9 parts to emulsify and disperse, then add 42.4 parts of a 5% aqueous solution of ethylenediamine, stir for 60 minutes, and heat to 40 to 50°C under reduced pressure in an evaporator.
to remove methyl ethyl ketone and determine the average particle size.
A milky white urethane resin emulsion with a diameter of 1.2 μm and a solid content of approximately 49% was obtained. Pigment paste (Fuji SP Blue431) 2 was added while stirring 100 parts of the obtained urethane resin emulsion.
1.0 parts of a thickener (Superflex VF, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to the mixture to prepare a urethane resin emulsion mixture. Next, a glove base (weighing: 35.5 g/pair) 1 manufactured by sewing cotton knitted cloth knitted from #40 cotton stockinette knitting yarn is heated to 70°C as shown in Figure 1. Insert it into a warmed aluminum hand mold 2, and as shown in FIG.
By slowly rotating the liquid surface of the bathtub 4 in the saucer 5 containing the urethane resin emulsion so as not to apply liquid pressure, the urethane resin emulsion is adhered to the surface of the glove base with few air bubbles and no decrease in viscosity. After gelation, a uniform wet film with a thickness of 100 to 500 μm was formed. Next, as shown in Figure 3, after hanging the mixture to remove excess compounded liquid, it is placed in a hot air drying oven at 100°C and heat-treated for about 10 minutes. I got coated work gloves. No cracks or rips were observed on the surface of the work gloves obtained, and a uniform film of urethane resin was formed. Furthermore, when the gloves were turned inside out and observed, the urethane resin had not penetrated into the fabric. Example 2 Polyoxytetramethylene glycol (average molecular weight 1000) 180 parts, polyethylene glycol (average molecular weight 600) 14.8 parts, polyoxyethylene oxypropylene random copolymer glycol (average molecular weight 3400) 14.8 parts, 1,4-butanediol 3.0 parts
77.5 parts of diphenylmethane diisocyanate was added to a mixture consisting of 5.1 parts of trimethylolpropane and 147.6 parts of methyl ethyl ketone, and the mixture was heated at 75°C.
Free isocyanate group content by reacting for 60 minutes
A solution of 0.36% urethane polymer (oxyethylene chain content 9.02%) in methyl ethyl ketone was obtained.
The resulting solution contains 14.8 parts of polyoxyethylene aryl phenol ether type nonionic surfactant (HLB=8), which is an ethylene oxide adduct of distyrenated phenol, and polyoxyethylene aryl phenol, which is an ethylene oxide adduct of distyrenated phenol. Add 14.8 parts of an ether-type nonionic surfactant (HLB=15) (total blending ratio of nonionic surfactants 9.12%) and 324.7 parts of water and emulsify to create a 5% aqueous solution of ethylenediamine.
After adding 15.2 parts and stirring for 60 minutes, the organic solvent was distilled off to obtain a milky white urethane resin emulsion with an average particle size of 1.2 μm and a solid content of about 50%. Pigment paste (Fuji SP Black8010) was added while stirring 100 parts of the obtained urethane resin emulsion.
Then, 0.5 part of a thickener (DK Thickener SCT-270, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was mixed in to prevent bubbles from forming to prepare a urethane resin emulsion mixture. Next, a urethane resin emulsion was applied to the same glove base as in Example 1 in the same manner as in Example 1 to form a uniform wet film with a thickness of 300 to 450 μm, and then heat treatment was performed in the same manner as in Example 1. We obtained urethane-coated work gloves with a thickness of 200 μm that have flexibility, water resistance, oil resistance, and solvent resistance. No cracks or rips were observed on the surface of the work gloves obtained, and a uniform film of urethane resin was formed. Furthermore, when the gloves were turned inside out and observed, the urethane resin had not penetrated into the fabric. [Effects of the Invention] According to the manufacturing method of the present invention, the urethane resin emulsion does not penetrate into the interior of the fabric of the glove base, and a thin and uniform film can be formed on the surface of the glove base. It is possible to manufacture work gloves with excellent water resistance, solvent resistance, etc. In addition, since no solvents are used in the manufacturing process, there are no problems such as fire, injury to the human body, or environmental pollution, and work gloves with excellent oil resistance, abrasion resistance, and cold resistance can be produced safely and quickly at low prices. It can be manufactured in

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the process of inserting the glove base into the hand mold, Fig. 2 is an explanatory diagram of the process of applying the urethane resin emulsion mixture to the glove base by dipping method,
FIG. 3 is an explanatory diagram of the process of removing excess urethane resin emulsion compounded liquid adhering to the glove base. (Main symbols in the drawing), 1: glove base, 2: hand shape.

Claims (1)

[Claims] 1. After inserting a fabric glove base into a heated hand mold, a urethane resin emulsion having heat-sensitive gelling properties is applied to the surface of the glove base, and then dried to produce work gloves. As the urethane resin emulsion, polyisocyanate and 2
Molecular weight 200-10000 with more than 1 active hydrogen atom
with the molar ratio of NCO/active hydrogen atoms
A urethane polymer having a free isocyanate group content of 0.2 to 1.5% by weight and an oxyethylene chain content of 5 to 20% by weight obtained by reacting in 1.02 to 1.2,
In the presence of water containing a nonionic surfactant with an HLB of 6 to 18 in an amount of 2 to 15% by weight based on the urethane polymer, two primary and/or secondary amino groups are added to each molecule. A method for manufacturing work gloves, characterized by using a nonionic urethane resin emulsion having heat-sensitive gelling properties obtained by chain extension with a polyamine compound containing the above.