JPH02184B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to a cushion material having a conductive layer on the surface of a foam. (Prior art) Examples of conductive urethane foam include a type in which carbon black is contained in the entire skeleton of a polyurethane foam as described in JP-A No. 59-84914, and a type in which carbon black is included in the entire skeleton of the polyurethane foam, as described in JP-A No. 59-84914;
115433 and 59-6255, in which a polyurethane foam is impregnated with an emulsion containing carbon black are known. However, in the former case, the viscosity of the urethane foaming stock solution containing carbon black is high and foaming is difficult, and the resulting foam is also hard and loses the original feel of the urethane foam. In the latter case, the entire urethane foam is impregnated with an emulsion containing carbon black, which also makes the foam hard and loses its original texture. (Problems to be Solved by the Invention) An object of the present invention is to provide a cushion material in which only the surface layer of the soft urethane foam is made conductive without impairing its original feel and cushioning properties. (Means for Solving the Problems) The present invention provides an aqueous conductive resin composition containing conductive carbon black in an aqueous cationic polyurethane dispersion on the surface of a foam so that the surface resistivity is 10 ⁹ Ω or less. The present invention relates to a cushion material having a surface conductive layer obtained by coating. The cushion material of the present invention can be used for various purposes, and in particular, it can be used as a cushion material for devices and their parts using ICs, static electricity shielding materials such as packing materials for these devices, materials for low frequency treatment devices, materials for static electricity treatment,
It is preferable to use it as a radio wave absorbing material. In the present invention, various foams can be used, including known foams that can be used as cushion materials, such as polyurethane foam, EVA foam, and polystyrene foam. The cationic polyurethane of the present invention can be obtained, for example, by reacting a polyol, a polyisocyanate, at least one tertiary amino group in the molecule, and two or more chain extenders and quaternizing agents having Zelevitinoff activity. In the present invention, various polyester polyols, polyether polyols, and other polyols can be used as the polyol. Examples of polyester polyols include those having 4 carbon atoms, such as adipic acid, suberic acid, sebacic acid, and brassylic acid.
~20 aliphatic dicarboxylic acids, terephthalic acid, isophthalic acid, etc. as acid components, and carbon atoms such as ethylene glycol, propylene glycol, neopentyl glycol, hexamethylene glycol, etc.
6 aliphatic diols, ether glycols such as diethylene glycol, dipropylene glycol,
Polyester polyols or polycaprolactone polyols containing spiroglycols, N-alkyl dialkanolamines such as N-methyldiethanolamine, etc. as polyol components can be used, and specific examples include polyethylene adipate polyol, polybutylene adipate polyol, and polyethylene propylene. Examples include adipate polyols such as adipate polyol, terephthalic acid polyols (e.g., Toyobo Co., Ltd., product names Vylon RUX, Vylon RV-200L), polycaprolactone polyols (e.g., Daicel Chemical, product names Plaxel 212, Plaxel 220), etc. can. Specific examples of polyether polyols include polyoxyethylene polyol, polyoxypropylene polyol, polyoxytetramethylene polyol, and the like. In addition, other polyols include polycarbonate polyol (e.g., West Germany, Bayer AG, trade name Desmofene 2020E), polybutadiene polyol (e.g., Nippon Soda, trade name G-1000, G-
2000, G-3000, Idemitsu Petrochemical, product name Poly
bdR-45HT), polypentadiene polyol,
Examples include castor oil-based polyols.
These polyols can be used alone or in combination of two or more. Various polyisocyanates can be used in the present invention, such as diphenylmethane diisocyanate (MDI), tolylene diisocyanate (TDI), tolidine diisocyanate (TODI), xylene diisocyanate (XDI), and naphthylene diisocyanate ( NDI),
Diisocyanates such as isophorone diisocyanate (IPDI), hexamethylene diisocyanate (HDI), dicyclohexylmethane diisocyanate (HMDI), and lysine diisocyanate (LDI); polyesters such as triphenylmethane triisocyanate, polymethylene polyphenyl isocyanate (PAPI), and carbodiimide-modified MDI. Examples include isocyanates, and these can be used alone or in combination of two or more. Furthermore, it is also possible to use those obtained by blocking a part of these isocyanates with a blocking agent. As the chain extender in the present invention, a chain extender having at least one tertiary amino group and two or more Zerewitinoff activities in the molecule is used. Examples of chain extenders having at least one tertiary amino group and two or more Tselevitinoff activities in the molecule mentioned above include N-methyldiethanolamine, N-ethyldiethanolamine, N-
Examples include butyldiethanolamine, bis-hydroxyethylpiperazine, N-phenyldiethanolamine, and the like. Further, in the present invention, ordinary chain extenders can be used in addition to the above-mentioned chain extenders, and preferable examples include those having the general formulas HO-R ¹ -OH, H ₂ N-R ² -NH ₂ , A(CH ₂ CH ₂ OH) ₂ , H ₂ N-B-NH ₂ (R ¹ is a linear or branched alkylene group having 2 to 10 carbon atoms, and may be connected through an oxygen atom. R ² is a C 2-C ~10 linear or branched alkylene groups or alicyclic values.A and B
is a group having an aromatic ring. ) Aliphatic diols, aliphatic diamines, aromatic diols,
Examples include aromatic diamines. Preferred examples of the aliphatic diol include ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, neopentyl glycol, diethylene glycol, dipropylene glycol, etc., and specific examples of the aliphatic diamine include ethylene diamine, 1,6
-Hexamethylene diamine, isophorone diamine, etc. can be mentioned. Further, as A of the above aromatic diol, for example,

【formula】

【formula】

【formula】

【formula】

【formula】 etc., and as aromatic diamine B,

【formula】

【formula】

[Formula] etc. can be exemplified. In the present invention, a chain extender having at least one tertiary amino group and two or more having Tzelevitinoff activity in a molecule that can be converted into an ionic group is quaternized in advance with a quaternizing agent, or By copolymerizing an extender into polyurethane and then quaternizing it with a quaternizing agent, the resulting aqueous polyurethane dispersion can be cationized. In the present invention, quaternizing agents include, for example, dialkyl sulfates such as dimethyl sulfate and diethyl sulfate, halogenated hydrocarbons such as methyl chloride, methyl iodide, ethyl bromide, and benzyl chloride, and organic acids such as acetic acid, propionic acid, and monochloroacetic acid. acid, hydroiodic acid,
Various quaternizing agents such as inorganic acids such as hydrobromic acid, hydrochloric acid, and perchloric acid can be used. In the present invention, each component may be appropriately determined from a wide range depending on the intended aqueous dispersion, but for example, the chemical equivalent ratio of active hydrogen groups contained in the polyol and chain extender to NCO groups of the polyisocyanate is It is preferable to react within a range of 0.9 to 1.4, preferably 0.95 to 1.1. The proportion of quaternized amino groups in the polyurethane is usually preferably 0.1 milliequivalent/g or more per polymer.
Further, in the present invention, an inert solvent that does not react with NCO groups can be used, and can be recovered by distillation if necessary. In addition, known urethanization catalysts and aqueous antifoaming agents (e.g., Toray Silicone, SM-
5512, made by San Nopco, SN defomer 113, 432
etc.), it is also optional to use an anti-yellowing agent (eg, hindered phenol type, hindered amine type, etc.) to impart weather resistance and heat discoloration resistance. Examples of the above-mentioned solvents include ketones such as acetone and methyl ethyl ketone, esters such as ethyl acetate and methyl propionate, ethers such as dioxane, tetrahydrofuran, and cellosolve acetate, and dimethylformamide, dimethylacetamide, dimethyl sulfoxide, and hexamethylphosphoric. Examples include triamide, N-methylpyrrolidone, etc., and these solvents may be used at any stage of the reaction of the present invention. The aqueous polyurethane dispersion of the present invention can be produced by various methods, such as a one-shot method or a prepolymer method. In the prepolymer method, for example, polyol and polyisocyanate are reacted.
An NCO-terminated prepolymer is created, then a chain extender is added and reacted, and if a chain extender that has not been quaternized is used, a quaternizing agent is then added to the resulting polymer. After cooling, water is added with vigorous stirring and the solvent is then distilled off to give a milky white emulsion. In this case, water may be added while distilling off the solvent. The prepolymerization reaction is usually preferably carried out at about 60 to 130°C. Further, it is preferable that the quaternization reaction is usually carried out at about 40 to 100°C. In the present invention, other emulsions can also be blended into the aqueous polyurethane dispersion obtained. Examples of other emulsions include vinyl acetate/vinyl chloride copolymer emulsion (e.g., Denka Kagaku Kogyo, trade name Denka Techs AC-20), ethylene/vinyl acetate copolymer emulsion (e.g. Denka Kagaku Kogyo, trade name Denka EVA Teks), etc. can be mentioned. Further, an aqueous solution of aliphatic polyamine such as ethylenediamine, diethylenetriamine, hexamethylenediamine, etc. may be used in combination with the aqueous polyurethane dispersion of the present invention. The aqueous conductive resin composition of the present invention can be obtained by blending conductive carbon black into the above-mentioned aqueous polyurethane dispersion. The conductive carbon black is not particularly limited and a wide variety of materials can be used, but preferred specific examples include butcher black, acetylene black, and the like. Product names include, for example, Ketuchen Black EC manufactured by Lion Corporation, ECDJ-600, and Cabot manufactured by Cabot.
Examples include Vulcan XC-72 and Toka Black #4500 and #5500 manufactured by Tokai Carbon Co., Ltd. The amount of carbon black to be blended is usually about 5 to 100 parts by weight, preferably about 5 to 100 parts per 100 parts of the polymer.
The amount is preferably 10 to 50 parts, and within this range excellent results can be obtained in terms of conductivity, gloss, film strength, adhesive strength, etc. Further, when dispersing carbon black, it may be added directly to the aqueous polyurethane dispersion, but it is preferable to prepare an aqueous dispersion of carbon black before adding it. When preparing this aqueous dispersion of carbon black, it is preferable to use a cationic surfactant, a nonionic surfactant, or the like. In the present invention, the cationic polyurethane aqueous solution and carbon black can be mixed using various known stirring devices. In addition, the aqueous conductive resin emulsion of the present invention includes known thickeners and protective colloid agents, such as polyvinylpyrrolidone, polyurethane aqueous solution (BASF, Colaclar 8500),
Hydroxyethyl cellulose, methyl cellulose, starches, polyvinyl alcohol, etc. can be added to increase the viscosity and stabilize the product during long-term storage. The conductive cushion material of the present invention can be obtained by applying the aqueous conductive resin composition containing the above-mentioned carbon black to the surface of a foam such that the surface resistivity is 10 ⁹ Ω or less. As a coating method, a known method can be used, such as a spray method or a coater method (gravure coater, roll coater, doctor blade, etc.).
Cushion materials with a surface resistivity of 10 ⁹ Ω or less will not be charged under any conditions when rubbed, but those with a surface resistivity exceeding 10 ⁹ will become charged due to friction in dry conditions (low humidity). Foams that are not coated with a conductive resin composition are strongly charged just by contact between the foams. (Example) Reference examples and examples will be described below.
Note that parts and % below indicate parts by weight and % by weight, respectively. Reference example 1 Production of conductive carbon black dispersion (A) Dissolve 2 parts of Cortamine 24P (cationic surfactant, manufactured by Kao Atlas Co., Ltd.) in 90 parts of water, and add 10 parts of carbon black (Ketsutien Black EC) while stirring with a homogenizer. of water and stir for 30 minutes.
A dispersion with a carbon black concentration of approximately 10 wt% and excellent storage stability was obtained. Reference Example 2 Production of cationic polyurethane emulsion (a) Nitsuporan 4009 (polybutylene adipate diol molecular weight 100, manufactured by Nippon Polyurethane Co., Ltd.)
150 g (b) MDI 75 g (c) N-methyldiethanolamine 10.7 g (d) 1,4-butanediol 5.4 g (e) Dimethyl sulfuric acid 11.3 g A 1 liter bottle equipped with a stirrer, thermometer, condenser and nitrogen inlet Put components (a) and (b) into a separable flask and react at 80°C for 1 hour. Next, add 504g of methyl ethyl ketone (MEK), and
Component (d) is added and reacted in a nitrogen atmosphere under MEK reflux until NCO absorption is no longer detected in the infrared absorption spectrum. Then, after cooling to 70℃, (e)
After adding the ingredients and stirring for 30 minutes, add 379g of water and MEK.
When distilled off, the solid content is 40wt% and the viscosity is 120cps/25
A milky white emulsion () was obtained. Example 1 Using a carbon black dispersion (A) and a cationic polyurethane emulsion (), an emulsion with a total solid content of 10% in which the solid content ratio of carbon black and polyurethane was 1/4 (weight ratio) was obtained. This was sprayed onto a 15 mm thick soft polyurethane foam to obtain a cushion material having a conductive layer on the surface. The relationship between solid content basis weight and surface resistivity is shown in A of FIG. Example 2 Using a carbon black dispersion (A) and a cationic polyurethane emulsion (), an emulsion with a total solid content of 10% in which the solid content ratio of carbon black and polyurethane was 1/8 (weight ratio) was obtained. This was sprayed onto a 6 mm thick soft polystyrene foam to obtain a cushion material having a conductive layer on the surface. The relationship between solid content basis weight and surface resistivity is shown in B of FIG.

[Brief explanation of drawings]

Figure 1 shows the solid weight and surface resistivity (Rs) of the conductive resin composition in the cushion material of the example.
This is a graph showing the relationship, where the area above the straight line C is charged due to friction, and the area below is not charged even when rubbed.

Claims (1)

[Claims] 1. A surface obtained by applying an aqueous conductive resin composition containing a cationic polyurethane aqueous dispersion and conductive carbon black to the surface of a foam such that the surface resistivity is 10 ⁹ Ω or less. A cushion material with a conductive layer. 2. The cationic polyurethane aqueous dispersion is obtained from a polyol, a polyisocyanate, a chain extender and a quaternizing agent having at least one tertiary amino group and two or more Zelevitinoff activities in the molecule. A cushion material according to claim 1. 3. The cushion material according to claim 2, wherein the chain extender is quaternized in advance with a quaternizing agent. 4. The cushion material according to claim 2, wherein the chain extender is copolymerized into polyurethane and then quaternized with a quaternizing agent.