AU783940B2 - A method for manufacturing heat-bondable sheet having water repellency - Google Patents

Description

S&F Ref: 578106

AUSTRALIA

PATENTS ACT 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT

ORIGINAL

Name and Address of Applicant: Actual Inventor(s): Address for Service: Invention Title: Nagoya Oilchemical Co., Ltd.

213-5 Honowari Minamishibata-cho Tokai-shi Aichi Japan Masanori Ogawa, Norihiko Kioka, Kuninori Ito Spruson Ferguson St Martins Tower,Level 31 Market Street Sydney NSW 2000 (CCN 3710000177) A Method for Manufacturing Heat-bondable Sheet Having Water Repellency The following statement is a full description of this invention, including the best method of performing it known to me/us:- 5845c 1 A METHOD FOR MANUFACTURING HEAT-BONDABLE SHEET HAVING WATER REPELLENCY FIELD OF THE INVENTION The present invention relates to a method for manufacturing heat-bondable sheet having water repellency used for such purposes as a hood silencer for the engine area of a car. and the like.

BACKGROULND OF THE INVENTION ,s For instance, a hood silencer for the engine area or a car consists ot a porous sheet and a surface laver which is bonded to the surface of said porous sheet. To bond said surface laver to the surface of said porous sheet. commonly a hot-melt sheet is used but since said hot-melt sheet has no gas permeability and hinders soundproof property of said hood silencer.

Accordingly. recently, a hot-melt adhesive powder is used to bond said surface layer to said porous sheet. In this case. a hot-melt adhesive powder is put on the bonding surface of said surface layer and said surface layer is piled on said porous sheet and then said surface layer and said porous sheet piled together are heated and pressed to bond.

As a method to put said hot-melt adhesive powder on the bonding surface of said surface laver, a method wherein said hot-melt adhesive powder is strewed on the bonding surface of said surface layer or a method wherein an aqueous dispersion of said hot-melt adhesive powder is sprayed on the bonding surface of said surface layer and then is dried is applied.

Nevertheless, the fiber sheet as said surface layer has the nap on the surface and when said hot-melt adhesive powder get in the root part of said nap, it is feared that said hot-melt adhesive powder may be covered by said nap to obstruct bonding.

Accordingly, recently a method wherein an aqueous dispersion of a hot-melt adhesive powder having the structural viscosity is sprayed on the bonding surface of said fiber sheet is proposed (WO 00/52110) DESCRIPTION OF THE PRIOR ART Up to now. for instance, in case of a hood silencer for the engine area of a car. water renellent finishing is carried out on the surface of said surface layer to protect from water seeping. To carry out said water repellent finishing on said surface la\ er. a method comprising impregnating an aqueous \vater repellent solution in said surface laver. heatin and drying. spraying said aaueous disoersion of said hot-melt adhesive co%,der on the bonding surface of said surface layer and heating and drying method 1 or a method comprising spraying said aqueous dispersion of said hot-melt adhesive powder in which a water repellent is mixed to the bonding surface of said surface layer and heating and drying (method 2) are presented.

In method two times of heating and drying process are necessary so that especially in a case where a long sheet is processed. said sheet must be passed through two sets of heat drier consuming time and raising the expense for equipment.

In particular, when first said aqueous water repellent solution is impregnated in said surface laver and heated and dried, and then said aqueous dispersion of said hot-melt adhesive powder is sprayed on the bonding surface of said surface layer, said aqueous dispersion of said hot-melt adhesive powder is repelled and a problem that uniform coating of said aqueous dispersion of said hot-melt adhesive powder can not be attained may be caused.

In method heating and drying process is one time but since said aqueous dispersion of said hot-melt adhesive powder has structural viscosity, said aqueous S dispersion containing said water repellent may remain on the bonding surface of said surface layer and can not reach the surface of said surface layer so that it may be impossible to give enough water repellency to the surface of said surface layer.

SUMMARY OF THE INVENTION Accordingly an object of the present invention is to spray said aqueous dispersion of said hot-melt adhesive uniformly on the surface of the heat-bondable sheet. Another object of the present invention is to carry out water repellent finishing effectively to the surface of the heat-bondable sheet. Further object of the present invention is to give enough bonding strength to the heat-bondable sheet.

To attain said object. the present invention provide a method for manufacturing heat-bondable sheet having water repellency comprising; impregnating an aqueous water repellent solution in a fiber sheet. spraying an aqueous dispersion of a hot-melt adhesive powder having structural viscosity on said fiber sheet. and while said fiber sheet is not dried completely, adhering said hot-melt adhesive powder on the upper part of nap on the surface of said fiber sheet.

It is preferable that said aqueous dispersion of said hot-melt adhesive powder is given structural viscosity by an alkali-thickening type thickener. and further it is preferable that a flame retardant is added in said aqueous water repellent solution and /or said aqueous dispersion of said hot-melt adhesive powder.

In the present invention, after said aqueous water repellent solution is impregnated in said fiber sheet, and while said fiber sheet is not dried completely, said aqueous dispersion of said hot-melt adhesive powder is sprayed on the surface of said fiber 1« sheet. Therefore said aqueous dispersion of said hot-melt adhesive powder is uniformly sprayed on the bonding surface of said fiber sheet without repelling.

Further, since said aqueous dispersion has structural viscosity, when said aqueous dispersion is spraved on the bonding surface of said fiber sheet, said aqueous dispersion is hard to flow on the bonding surface of said fiber sheet so that said aqueous dispersion can be uniformly sprayed easily on the bonding surface and as said aqueous dispersion is hard to get in the root part of the nap of the bonding surface of said fiber sheet, said hot-melt adhesive powder is mostly adhere to the upper part of said nap.

3€' BRIEF DESCRIPTION OF THE DRAWINGS t, Fig. 1 is a schematic side sectional view of the manufacturing process of the heat-bondable sheet having water repellency (surface layer) of an embodiment.

Fig. 2 is a side sectional view of the heat-bondable sheet having water repellency (surface laver) of an embodiment.

Fi. 3 is a schematic side sectional view of bonding the heat-bondable sheet having water repellency (surface layer) of Fig. 2 with the base of the interior (cushion laver).

Fi. 4- is a side sectional view of the interior of an embodiment.

[AN EXPLANATION OF CODES] a heat-bondable sheet havin, w ater re.eiilency S a cushion layer (a base of an interior 3 A a fiber sheet a surface laver 4 an adhesive laver *5 an interior DETAILED DESCRIPTION [Aqueous water repellent solution] Water repellent used water repellent finishing of said fiber sheet in the present invention may be common water repellent such as hydrocarbon derivative such as paraffin, wax, and the like, fatty acid derivative. organopolysiloxane. fluorocarbon, zirconium salt of fatty acid, and the like and said water repellent is used as aqueous liquid type such as aqueous dispersion, aqueous emulsion and the like. Usually 0.05 to 20 by weight of said water repellent is contained in said aqueous liquid.

[Aqueous dispersion of a hot-melt adhesive powder] In the present invention, as hot-melt adhesive. polyolefin type resin such as polyethylene, polypropylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer and the like, modified polyolefin type resin, polyvinyl chloride, polyurethane, polyester, polyester copolymer, polyamide, polyamide copolymer and the like may be used singly or as a mixture of two or more kinds. The particle size of said hot-melt adhesive is usually in the range between 50 to 300 mesh.

Said hot-melt adhesive powder is dispersed in water and an aqueous dispersion is prepared. In order to give structural viscosity to said aqueous dispersion. a water soluble thickener is added. As said water soluble thickener, the following agents are used. for instance. polvacrylic acid and salts of polymethacrylate. such as sodium olvacrvlate. ammonium polvacrylate. sodium polvmethacrylate. ammoniumrn oolvmethacr late. and the like. polvvinyl alcohol. polyethylene oxide. calboximelthy cellulose. methvL cellulose, viscose. starch. denatured starch. casein. gelatin. gum arabic. Dsectin and the like.

When said water soluble thickener is to be dissolved in water. clods are liable to be ornme. Therefore. much preferable thickener in -he present invention is an aikali-thicKening type thickener.

A Cesirable alkali-thickening type thickener is an alkali-thickening type acrylic emulsion and the other desirable alkali-thickening type thickener is a slightly cross-linked polvacrylic acid.

Said alkali-thickening type acrylic emulsion may include a copolymer of acrylic ester and a,P-unsaurated carboxylic acid, a copolymer of acrylic ester. another .vinyl monomer(s) which can be copolymerized with said acrylic ester, and u P.3-unsaturated carboxvlic acid.

As said acrylic ester, methyl acrylate. ethyl acrylate. n-propyl acrylate, isopropyl acrlate. n-butyl acrylate, isobutyl acrylate, t-butyl acrylate. 2-ethylhexyl acrylate, cvclohexvl acrylate, tetrahydrofurfuryl acrylate methyl methacrylate, ethyl S M methacrylate, n-propyl methacrylate. isopropyl methacrylate. n-butyl methacrylate.

isobutyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate.

tetrahydrofurfuryl methacrylate. stearyl methacrvlate. laurvl methacrylate, P-hvdroxyethyl acrylate, P-hydroxyethyl methacrylate, P-hvdroxypropyl acrylate.

P-hvdroxypropyl methacrylate dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, glycidyl acrylate, glycidyl methacrylate and the like may be used.

As said a,P-unsaturated carboxylic acid, such as acrylic acid. methacrylic acid.

maleic acid. itaconic acid, crotonic acid, atropic acid, citraconic acid and the like may be used.

As a vinyl monomer which can copolymerize with said acrylates, a vinyl ether monomer such as methylvinyl ether, ethylvinyl ether, n-propylvinyl ether, n-butvlvinyl ether, isobutylvinyl ether and the like, styrene and styrene derivative (a-methlvstyrene and the like), a vinyl monomer having a cyano group such as acrylonitrile methacrylonitrile and the like, a vinyl monomer having an isocyanate group such as acryloilisocyanate. methacryloilisocyanate, Sm-isopropenvl-a.a-dimethylbenzylisocyanate and the like. a vinyl monomer having an amide group such as diacetoneacrylamide. N-vinylformamide. N-vinylacetoamide and the like. a vinyl monomer having a sulfonic acid group such as p-stvrene sulfonic acid. 2-(acrvloilamino)-2-methylpropane sulfonic acid and the like. a vinyl monomer having a mercapto group such as mercaptopropyltrimethoxysilane.

0 mercaptopropyltriethoxysilane and the like are used.

In said acrylic emulsion, said a,.-unsaturated carboxylic acid may by copolymerized in an enough amount to give a water soluble copolymer when said copolymer is neutralized by an alkali agent. Said amount of said a.p-unsaturated carboxvlic acid may be changed by the kinds of acrylic ester, another vinyl monomer, and said a,3-unsaturated carboxylic acid but usually said a.3-unsaturated carboxvlic acid is contained in said copolymer at an amount in the range between to 60 by weight, desirably 30 to 50 by weight.

tSaid acrylic copolymer may be cross-linked with one another if they can be soluble in water. In this case, said copolymer has some multifunctional vinyl monomer such as divinyl benzene, methylene bisacrylamide. ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylol propane dimetacrylate. trimethylol propanetrimetacrylate, diallyl phtalate and the like.

To prepare a dispersion of a hot-melt adhesive powder using said alkali-thickening type acrylic copolymer emulsion as a thickener, first said acrylic emulsion and a hot-melt adhesive powder are added to water to make a dispersion by stirring. At this stage, it is very easy to make a uniform dispersion since the viscosity of said Sdispersion is not yet increased.

Said hot-melt adhesive powder is not always added in the water at the same time of said acrylic emulsion and may be added in the water at any stage but preferably added in the water before thickening.

Said hot-melt adhesive powder is usually dispersed in water in the range of 1 to by weight. Said acrylic copolymer emulsion is added to said water in order to adjust a viscosity of a dispersion of the hot-melt adhesive powder thickened by alkali in the range of 50 to 2000 mPa -s 25 For example, in the case of using a emulsion containing 30 by weight of copolymer which is copolymerized of ethylacrylate and methacrylic acid in the weight ratio of 6 4, said emulsion is added to said water in the amount of 0.1 to 10 by weight of said emulsion.

The alkali is added to the water after acrylic copolymer emulsion and the powder of the hot-melt adhesive are added to the water and mixed uniformly. Said copolvmer becomes soluble in water because carboxylic acid coming from -unsaturated carboxylic acid becomes a salt so that said salt thickens said dispersion.

A.s said alkali. ammonia, amine. hydroxide of alkaline metal or alkali earth metal such as sodium hydroxide, potassium hydroxide, barium hydroxide. calcium hydroxide and the like, oxide of alkali earth metal such as lime and the like, weak acid salt of alkaline metal such as sodium carbonate. sodium sulfite, sodium acetate.

sodium phosphate and the like, may be used.

The adding amount of said alkali agent is commonly decided so that pH of said Sdispersion is adjusted to be in the range between 6 to 9.

As above described, said aqueous dispersion of a hot-melt adhesive powder using said alkali-thickening type acrylic emulsion as a thickener shows the plastic flow to prevent the sedimentation of said hot-melt adhesive powder.

On the other hand, said slightly cross-linked polyacrylic acid as the other desirable alkali-thickening type thickener is usually produced by a deposition polymerization method as below described.

In said deposition polymerization, a solvent in which acrylic acid can be dissolved and polyacrylic acid cannot be dissolved is used. Said solvent may be such as benzene, ethylacetate, cyclohexane, toluene and the like or a mixture of two or more solvents above-described and acrylic acid, a cross-linking agent, and an initiator are added in said solvent to polymerize.

As cross-linking agent that multifunctional vinyl monomer such as divinyl benzene, diallyl phtalate, tetraalloxy ethane, ethylene glycol propane dimetacrylate, 8 polyethylene glycol dimetacrylate, trimethylol propane dimetacrylate and the like, sugar derivative such as allvlsaccharose and the like may be used. Ordinarily, said cross-linking agent may be added to acrylic acid below 1 preferably about 0.05 by weight.

As a polymerization initiator, for example, peroxide polymerization initiator such as benzoyl peroxide. methyl ethyl ketone peroxide. cumenehydro peroxide. t-butylhydro peroxide. cyclohexyanone peroxide. t-butyl peroxide. t-butylperoxy benzoate.

t-butvlperoxy-2-ethylhexanate, t-butylperoxy pivalate. t-butylperoxy neodecanenate.

'o 3.5.5-trimethlhexanoil peroxide. diisopropylbenzene hydro peroxide. lauroyl peroxide, diglyme peroxide, azo polymerization initiator such as 2.2'-azobisisobutrronitrile, 2.2'-azobis-2-methylbuthyronitrile, 2.2'-azobis-2.4'-dimethvlvaleronitrile, 2.2'-azobis-2-cycropropylpropionitrile.

2.2'-azobis-4-methoxy-2.4-dimethlvaleronitrile.

1. l1'-azobiscyclohexane-l-carbonitrile.

2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 2.2'-azobis-N.N'-dimethyleneisobutiramide and the like, may be used.

When acrylic acid is polymerized in said solvent as above described, a slightly cross-linked polyacrylic acid may deposit and depositing polyacrylic acid powder is collected and dried. The resulting polyacrylic acid is slightly cross-linked in a low density so that said polyacrylic acid maintains water solubility. When the cross-linking density of said polyacrylic acid becomes higher, said polyacrylic acid does not dissolve in the water but swells by adsorbing water and when the '.i cross-linking density of said polyacrylic acid becomes much higher, said polyacrylic acid becomes insoluble in the water.

To prepare said aqueous dispersion of a hot-melt adhesive powder, first, said slightly cross-linked polyacrylic acid and said hot-melt adhesive powder are added in the water to produce a dispersion by stirring. At this stage, said dispersion has comparatively low viscosity so that said slightly cross-linked polyacrylic acid does not substantially produce clod, and it is easy to make a uniform dispersion.

Further, it is not always necessary that said hot-melt adhesive powder and said Sslightly cross-linked polyacrylic acid are added together at the same time and said hot-melt adhesive powder may be added at any stage but preferably before thickening.

9 Commonly, said hot-melt adhesive powder may be dispersed in the water in an amount in the range between 1 to 60 by weight, and said slightly cross-linked polyacrylic acid may be added so that the viscosity of the resulting dispersion becomes in the range between 50 to 2000 mPa -s 25 °C.

Said slightly cross-linked polvacrylic acid added in the water dissolves in the water to increase slightly the viscosity of the water and when alkali agent is added in said water to neutralize said polvacrylic acid, the viscosity of said water is remarkably increased because the neutralized polvacrylic acid expands its chain by reciprocal c electrostatic repelling force of each carbanion.

It is preferable that ammonia, amine such as triethanolamine. diisopropanolamine.

aminomethvlpropanol. trimethvlol aminomethane, tetrahydroxyethlenediamine and the like may be used as said alkali. Also sodium hydroxide, potassium hydroxide and the like can be used. Said alkali agent may be added in an amount so as to adjust pH in the range between 6 to 9.

Further a part of a carboxyl group in said slightly cross-linked polyacrylic acid may be neutralized by alkali agent but when said carboxyl group is highly neutralized, clod is apt to be produced, so neutralized degree should be settled to be low to avoid producing clod.

Said aqueous dispersion of a hot-melt adhesive powder using slightly cross-linked polyacrylic acid as a thickener shows plastic flow to prevent substantially the 74 sedimentation of the hot-melt adhesive powder.

Further said alkali-thickening type acrylic emulsion and said slightly cross-linked polyacrylic acid may be used together in said aqueous dispersion of a hot-melt adhesive powder of the present invention.

A surface-active agent such as an anionic surface-active agent, a nonionic surface-active agent and a cationic surface-active agent may be added to said aqueous dispersion of a hot-melt adhesive powder as thickener. As the anionic surface-active agent such as higher alcoholsulfate (Na salt or amine salt), alkylarylsulfonate (Na salt or amine salt), alkylnaphtalenesulufonate (Na salt or amine salt), alkylnaphtalenesulufonate condensation, alkylphosphate, dialkylsulfosuccinate. rosin soap, fatty acid salt (Na salt or amine salt) and the like can be used. As the nonionic surface-active agent such as polyoxyethylene alkylether, polyoxyethylene phenolether, polyoxyethylene alkylester, polyoxyethylene alkvlamine, polyoxyethylene alkylolamine. polyoxyethylene alkylamide. sorbitan s alkvlester, polyoxyethylene sorbitan alkylester, and the like can be used. As the cationic surface-active agent such as octadecyl amineacetate. imidazolinederivative aceteate, polyalkylene polyamine derivatives or salt thereof. octadecyl trimethyl ammonium chroride. trimethyl aminoethyl alkyltriamide halogenide and the like can be used. Said thickener max be used singly or as a mixture of said surface-active 1o agent.

Further, for example. synthetic resin emulsion such as polyethylene, polypropylene.

ethylene-propylene copolymer, ethylene-vinylacetate copolymer, polyvinyl chloride.

polyvinylidene chloride, polystyrene, polyvinylacetate. fluororesin, thermoplastic is acrylic resin, thermoplastic polyester, thermoplastic polyamide. thermoplastic urethane and the like, thermosetting synthetic resin such as epoxy resin. melamine resin, urea resin, phenolic resin, resorcin resin, alkylresorcin resin and the like, acrylonitrile-butadiene copolymer, styrene-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer and the like; synthetic rubber or elastomer z powder, or synthetic rubber or elastomer emulsion such as acrylic rubber, butyl rubber, silicone rubber, urethane rubber, fluorinated rubber, polysulfide rubber, graft rubber, butadiene rubber, isoprene rubber, chloroprene rubber, polyisobutylene rubber.

polybutene rubber, isobutene-isoprene rubber, acrylate-butadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, pyridine-butadiene rubber, s styrene-isoprene rubber, acrylonitrile-chloroprene rubber, styrene-chloroprene rubber, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-hydrogen addition polyolefin-styrene copolymer, block copolymer such as butadiene-styrene block copolymer, styrene-rubber intermediate block styrene copolymer and the like may be added to said dispertion of the hot-melt adhesive ,o powder. Furthermore, if necessary, a filler such as calcium carbonate, talc, gypsum.

silica, carbon black, wood powder, walnut powder, coconuts powder, starch and the like, cellulose and celllose derivative such as carboxymethylcelllose, methylcelllose, hydroxymethylcelllose and the like, a pigment, dye, an insect repllent, antiseptic, an antioxidant, an UV absorber, fluoresent dye, a surface-active agent, a blowing agent, s a softener agent such as paraffin, wax, silicone and the like, an oil repllent agent, a release agent, a plasticizer and the like may be added to said aqueous dispersion of hot-melt adhesive powder.

11 In a case where said aqueous dispersion of a hot-melt adhesive powder is alkalized by said third component(s) or another alkali materials, said aqueous dispersion of a hot-melt adhesive powder is thickened by adding said alkali-thickening type thickener.

[Heat sensitive adhesive sheet] As a fiber sheet used for said heat sensitive adhesive sheet of the present invention.

there are. for example, synthetic fiber such as polyester fiber, polyethylene fiber.

polypropylene fiber, polyamide fiber. acrylic fiber. urethane fiber. polyvinyl chloride o fiber. polyvinylidene chloride fiber. acetate fiber and the like. natural fiber such as pulp, cotton, wool. coconut fiber, hemp fiber. bamboo fiber and the like. inorganic fiber such as glass fiber, carbon fiber. ceramics fiber, asbestos and the like. reused c fiber gotten by unweaving scrapped textile made by above-mentioned fibers, textile fabric or non-woven fabric made of one kind of or two or more kinds of above-mentioned fiber A fluffing layer mav be formed on said fiber sheet by needling or tufting.

A desirable fiber sheet is thermoforming non woven textile that is a mixture of one of following fibers with a melting point of 250 °C or more such as a polyester fiber, a >o polyamide fiber, a natural fiber, an inorganic fiber and the like; and one or two or more following fibers with a melting point 200 °C or under such as a polyester fiber, a polyamide fiber, polyethylene fiber, a polypropylene fiber and the like. Said fiber sheet is to undergo water repellent finishing in the first place.

As said water repellent finishing, said fiber sheet is soaked in an aqueous water repellent solution. The impregnated amount of said water repellent is controlled according to density of said agent in said solution or said impregnated amount in said solution. Said impregnated amount in said solution is controlled through squeezing said fiber sheet with squeeze rolls in said solution or through squeezing said fiber sheet with squeeze rolls after taking out from said solution.

Usually in said fiber sheet, said water repellent as solid is impregnated in the range between 0.01 g/m 2 to 20 g/m 2 i. After said aqueous water repellent solution is impregnated into said fiber sheet with a spray method or an impregnation method, and before said aqueous water repellent solution impregnated in said fiber sheet is dried up, said aqueous dispersion of a hot-melt adhesive powder is sprayed on a bonding surface of said fiber sheet.

To coat said aqueous dispersion of a hot-melt adhesive powder on the surface of said S fiber sheet, it is preferable to spray said aqueous dispersion on said surface.

applying high pressure. In this spray method, said aqueous dispersion can be effectively sprayed and coated even if said dispersion has a high viscosity. In this spray method. said aqueous dispersion of a hot-melt adhesive powder may be stirred but need not alwavs be stirred. The coating amount may be commonly in the Srange between 1 gm- to 100 Further. said aqueous dispersion of a hot-meit adhesive powder may be previously prepared in a high concentration. In this case, said aqueous dispersion of a ~hot-melt adhesive powder may be diluted by the water when said aqueous dispersion of a hot-melt adhesive powder is used.

As said aqueous dispersion of a hot-melt adhesive powder has structural viscosity, when said aqueous dispersion of a hot-melt adhesive powder is sprayed on the surface having naps, said aqueous dispersion of a hot-melt adhesive powder does not o enter into spaces between naps and is held on the surface and effectively fixed on the surface after drying. Further the sedimentation of said hot-melt adhesive powder is effectively prevented in said aqueous dispersion of a hot-melt adhesive powder, and the hot-melt adhesive powder is uniformly coated on the surface.

When said aqueous dispersion of hot-melt adhesive powder is sprayed on the bonding surface of said fiber sheet, it is preferable to aspirate from the opposite surface. Thus, by aspirating, rebounding of said hot-melt adhesive powder by an impact of the spraying can be prevented, and said hot-melt adhesive powder can surely be adsorbed on the bonding surface of said fiber sheet.

After said aqueous dispersion of hot-melt adhesive powder is coated by spraying as stated above, said fiber sheet is dried by heating. As a condition of said drying by.

heating, the temperature should be the melting point or over of the hot-melt adhesive used, usually 70 'C or over for 1 to 10 minutes. In this manner, said heat sensitive adhesive sheet is produced.

[Flame Retardant Treatment] 13 In the case where said heat sensitive adhesive sheet is used as a surface layer of a car interior which is arranged near a heat generating body, such as a hood silencer of the engine area, it is preferable to give it flame retardant treatment.

As flame retardants used for flame retardant treatment, the following agents are usually used. for instance, inorganic flame retardants such as ammonium bromide.

ammonium chloride. ammonium phosphate, ammonium sulfate. zinc chloride.

aluminium hydroxide. magnesium hydroxide, antimony troxide, antimony pentoxide.

zinc boric acid. barium metabolic acid. molybdenum oxide and the like. organic flame retargents such as halogenated compounds, phosphorus compounds, nitrogenous compounds, sulfuric compounds and the like. flame retardant synthetic resins such as chlorinated synthetic resins including vinylidene chloride resin, vinyl chloride resin and the like. and fluorinated synthetic resins including vinyl fluoride resin and the like, and so on. Two or more of these flame retardants may be mixed and in particular. by I- mixing inorganic and organic agents an exceedingly effective flame retardant can be produced.

It is desirable to add these flame retardants in aqueous water repellent solution or in aqueous dispersion of hot-melt adhesive powder.

The resulting heat sensitive adhesive sheet can be used as a surface layer of the car interior such as a hood silencer for the engine area, as a backing layer of a car interior base, as automobile carpet, as padding for garments, and the like.

[Interior] An interior of the present invention consists of said heat sensitive adhesive sheet as a surface layer and a base of the interior on which said surface layer is attached.

As said base of the interior, the following fibers can be used, for example, a synthetic fiber such as polyester fiber, polyethylene fiber, polypropylene fiber, polyamide fiber, aramid fiber, acrylic fiber, urethane fiber, polyvinyl chloride fiber, polyvinylidene chloride fiber, acetate fiber, rayon, cupro and the like; a wood fiber such as pulp, a chip of wood and the like; a natural fiber such as cotton, wool, silk, hemp, kenaf fiber, coconut fiber and the like; an inorganic fiber such as glass fiber, asbestos, ceramics fiber, carbon fiber, metal fiber and the like; a mixture of two or more kinds of said fibers, reused fiber gotten by unweaving scrapped textile made of above-mentioned fibers, a fiber sheet produced by binding above-said fibers with the 14 following resins or precursors such as a thermoplastic synthetic resin such as polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinylacetate copolymer, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinylacetate, fluororesin, thermoplastic acrylic resin, thermoplastic polyester, Sthermoplastic polyamide, thermoplastic urethane, acrylonitrile-butadiene copolymer, stvrene-butadiene copolymer, acrylonitrile-butadiene-styrene copolymer and the like, a thermosetting synthetic resin such as urethane resin, melamine resin. thermosetting acrylic resin, urea resin, phenolic resin, resorcin resin, alkylresorcin resin, epoxy resin, thermosetting polyester and the like, a synthetic resin precursor such as a prepolymer such as urethane resin prepolymer, epoxy resin prepolymer, melamine resin prepolymer, urea resin prepolymer, phenolic resin prepolymer, diallylphtalate prepolymer, acrylic oligomer, polyisocyanate, methacrylester monomer, diallylphtalate monomer and the like, oligomer, monomer and the like. Further, as said base of the interior, a needle punching felt manufactured by needle punching of a card web of said fiber to entangle fibers respectively; a synthetic resin impregnated felt in which said synthetic resin and/or said synthetic resin precursor is(are) impregnated; a thermoplastic felt manufactured by needle punching and/or heat setting of a mixture of said fiber and one or more kinds of a resin having a low melting point below 200 0 C such as polyethlene fiber, polypropylene fiber, polyester C* ao fiber, polyamide fiber and the like; a synthetic resin foam sheet such as melamine resin, polyurethane, polystyrene, polyvinyl chloride and the like; a reinforced synthetic resin foam sheet to which said fiber sheet is added as reinforcement fiber; a synthetic resin foam impregnated sheet in which said synthetic resin and/or said synthetic resin precursor is(are) impregnated; a cardboard or a used paper into which said synthetic resin or said synthetic resin precursor is impregnated; a lamineted base sheet with which two or more kinds of said fiber sheet are laminated; and the like can be used. Foaming agent may be added to said synthetic resin or said synthetic resin precursor which is used for said base of the interior. Said base of the interior is given a moldability by said synthetic resin, synthetic resin precursor or fiber with a low melting point, and the like used as a binder or impregnation agent.

In said base of the interior, it is desirable to impregnate a precondensate of said thermosetting synthetic resin in said porous material and further it is preferable to heat, dry, and condensate slightly said precondensate to be at B-stage.

When said precondensate in said porous material is condensated to be at B-stage, time to cure said precondensate can be shortened and preferable moldability of said base of the interior may be given in a short hot-press time while said porous material in which said precondensate is impregnated has a long storage life. In said base of the interior, since said precondensate may be completely cured by the hot-press, a base of the interior having the excellent dimensional stability and the Sheat resistance can be provided.

Said precondensate of said thermosetting synthetic resin may preferably be a phenolic precondensate which is a precondensate of a monohydric phenol and/or a polyhydricphenol and aldehyde. and said phenolic precondensate may preferably be sulfomethylated and/or sulfimethylated.

Said porous material includes organic or inorganic fiber material such as non-woven fabric. felt, fabric, knitting, their laminated sheet and the like; foamed plastic having a connected cell structure such as foamed polyurethane, foamed polyolefine such as foamed polyethylene, foamed polypropylene and the like, foamed polvvinyl chloride.

foamed polystyrene, foamed amino resin such as foamed melamine resin, foamed urearesin and the like, foamed phenolic resin and the like; sintering material of plastic beads and the like.

•e To attach said surface layer to said base of the interior, said hot-melt adhesive powder on the backside of said surface layer is softened by heating and then said surface layer is put on said base of the interior to attach together. In a case where said base of the interior is molded in a desirable shape, said molding may be carried out before said surface layer is attached to said base or when said surface layer is attached to said base or after said surface layer is attached to said base.

In a case where said base contains a thermoplastic resin or a thermoplastic fiber having a low melting point, said base is first heated to soften said thermoplastic resin or said thermoplastic fiber and then said base is molded by the cold press or in -a case where said surface layer has no gas permeability, the vacuum forming can be applied and in a case where said base contains a thermosetting synthetic resin, said base may be molded by the hot press.

As said surface layer is made of a fiber sheet and said hot-melt adhesive powder is dotted on the bonding surface, said surface layer has gas permeability and in a case where said base is molded after said surface layer is attached on said base, the air or the gas generated from the synthetic resin contained in said base of the interior, such 16 as formaldehyde gas in the case of a phenol resin, carbon dioxide gas or water in the case of polyisocyanate, can be smoothly discharged to the outside passing through the space between said dotted hot-melt adhesive powder on the fiber sheet so that no puncture may be produced in the resulting interior and the problem of the smell of the remaining gas is solved.

Said interior of the present invention can be provided for various uses such as a hood silencer of the engine area of the car. a trunk lining, or a dashboard covering. In said interior. since an adhesive layer of said hot-melt adhesive powder is dotted 'e between said base and said surface layer, the rigidity of said adhesive layer less affects the mechanical properties of said interior and as a result, the rigidity of said adhesive layer less affects the molded shape of said interior or the embossing :i design of the surface of said interior so a sharp molded shape or a sharp embossing "desin of said interior can be ensured. Further where said surface layer has a gas permeability, as said adhesive layer also has gas permeability, the resulting interior has an excellent soundproof property.

o The following is what we explain the present invention concretely with examples, however these examples are illustrative and therefore the scope of the invention is not restricted by them.

[EXAMPLE 1] To prepare each dispersion sample Al to A8 whose formulation is shown c in Table 1, polyamide hot-melt adhesive powder having a particle size of 250 mesh pass was dispersed in water and ethylacrylate-methacrylic acid copolymer emulsion having a solid content of 30 by weight as a thickener a or a slightly cross-linked polyacrylic acid (Junron PW-110 Nihon Junyaku Co.) as a thickener b were respectively added in said dispersion by stirring to make an uniform dispersion.

SAmmonia water was then added in said dispersion for thickening.

The resulting dispersion samples Al to AS were respectively put in 200cc glass bottles and kept for 2 months at the room temperature. After two months, storage stability of each sample was checked. The results are shown in Table 1.

[Table 1] 17 Dispersion 0 0A-1 A-2 A-3 A-4 A-5 A6 A-7 A-8 Polyamide powder 5 I20 30 40 5 20 30 IThickener a 2.5 2.0 1.8 iThickener b 0.5 0.4 0.2 0.1 I _ni wt 2.0 I i Ammonia water 2.0 1.8 1.5 1.0 2.0 2.0 1.7 :water 95 80 70 60 95 80 70 pH 7.9 7.7 7.5 7.2 8.2 8.0 8.0 7.9 41410 780 85 104 0 Viscosity (mPa -s/25°C) 410 680 750 920 410 780 850 1040 Storage stability O no sedimentation slight sedimentation [COMPARISON 1] Samples of dispersion of a hot-melt adhesive powder A9 to A12 whose formulations are shown in Table 2 respectively were prepared by the same method of EXAMPLE 1 excepting that said thickeners a. b and ammonia water were not added in each dispersion and storage stability of each sample was checked. The results of the :o checking of the storage stability are shown in Table 2.

[Table 2] Dispersion Polyamide powder water pH Viscosity (mPa *s/250C) Storage stability A-9 A-10 A-11 A-12 5 20 30 95 80 70 6.5 6.5 6.6 6.6 120 350 600 780 Sedimeta- Sedimeta- Sedimeta- Sedimetation tion tion tion 1 minute 2 minutes 4 minutes 5 minutes later later later later [COMPARISON 2] Excepting that 0.5 by weight of polysodiumacrylate aqueous solution was used instead of said thickeners a, b and ammonia water, dispersion of a hot-melt adhesive 18 powder samples A13 to A16 whose formulations are shown in Table 3 were respectively prepared by the same method of EXAMPLE 1 to check the storage stability. The result of checking stability of each sample is shown in Table 3.

r [Table 3] Dispersion A-13 A-14 A-15 A-16 Polyamide powder 5 20 30 polysodium- ,o acrylate aqueous 2.5 2.0 1.8 solution water 95 80 70 H 6.7 6.8 6.8 S. Viscosity (mPa s/25 0 C) 400 650 820 1050 S. Sedimeta- Sedimeta- Sedimeta- Sedimetation tion tion tion Storage stability 5 minutes 20 minutes 1 hour 2 hours later later later later As shown in Table 1 to Table 3 relating EXAMPLE 1, COMPARISON 1, and COMPARISON 2, each dispersion in EXAMPLE 1 shows an excellent storage stability while each dispersion without a thickener in COMPARISON 1 shows a poor storage stability and each dispersion in COMPARISON 2 also shows a poor storage stability even polysodium acrylate was used as a thickener in this

COMPARISON.

[EXAMPLE 2] A dispersion of a hot-melt adhesive powder B was prepared by dispersing 15 parts .c by weight of an ethylene-vinyl acetate copolymer (EVA) powder having a particle size of 200 mesh pass in 85 parts by weight of the water and 0.1 part by weight of sodium dialkylsulfosuccinate as a dispersing agent and 1.5 parts by weight of n-butylmethacrylate-itaconic acid copolymer emulsion as a thickener were added in said dispersion and stirred. Further, ammonia water was added to adjust pH of said dispersion 8.0 and the viscosity of the resulting dispersion of a hot-melt adhesive powder B was 310 mPa -s/25 OC.

Said dispersion B was kept at the room temperature and no sedimentation was produced after storage of more than 3 months to keep an excellent stability.

19 A dispersion of a hot-melt adhesive powder C was prepared by dispersing 15 parts by weight of an ethylene-vinyl acetate copolymer (EVA) powder the same as said dispersion B was dispersed in 85 parts by weight of the water and 0.1 part by weight of sodium dialkylsulfosuccinate as a dispersing agent and 0.5 part by weight r of a slightly cross-linked polvacrylic acid (Junron PW-150 Nihon Junyaku Co.) as a thickener were added in said dispersion and stirred. Further ammonia water was added to adjust pH of said dispersion 8.0 and the viscosity of the resulting dispersion of a hot-melt adhesive powder C was 720 mPa s 25 'C.

Said dispersion C was stored at the room temperature and no sedimentation was produced after storage more than 3 months to keep an excellent stability.

.A heat sensitive adhesive surface laver and an interior were manufactured by using said dispersion B and C by the following process.

A needle punching non-woven fabric made of a polyester fiber (unit weight 120 /im 2 was used as a surface layer (a fiber sheet).

As shown in Fig. 1, said fiber sheet (3A) was pulled out from a sheet roll S, by way of guide rolls (17, 18, 19) impregnated in a processing tub (16) filled with a dispersion of 2 by weight of a fluorocarbon type water repellent. After that, said fiber sheet (3A) was taken out from said processing tub and the content of said water repellent was controlled at 0.5 g/m 2 as solid. Said fiber sheet was introduced on a belt conveyer (21) having a gas permeability consisting of a net, a felt and the 2 like wherein a suction box (22) to which a vacuum path (23) with a valve (24) connects was attached to the backside of said belt conveyer (21) and said fiber sheet (3A) was vacuum-sucked by said suction box (22) through said belt conveyer In this condition said dispersion of a hot-melt adhesive powder B and C were respectively sprayed from a spray apparatus (25) arranged above said belt conveyer S(21) to coat said dispersion B and C on the surface of said fiber sheet (3A) which was not dried yet. Said dispersion B and C were respectively filled in a spray tank (26) of said spray apparatus (25) and said dispersion B and C were respectively stirred by a stirrer (28) and pressed by the high pressure air from a pressure pipe (27) in said spray tank (26) and said dispersion B and C were respectively sprayed Sfrom said spray apparatus As above described, said dispersion B and C were respectively coated on the surface of said fiber sheet (3A) in an amount of 5 g!m 2 as solid by spray. When said dispersion B, C respectively were coated on the surface of said fiber sheet (3A) by spraying, since said fiber sheet (3A) is sucked by said suction box (22) from the backside, said hot-melt adhesive powder in each dispersion B or C is sucked on the surface of said fiber sheet (3A) without splashing by the impact of spraying.

After coating said dispersion B. C respectively by spraying. said fiber sheet (3A) was introduced into a drying chamber (29) and dried at 170 'C for 2 minutes. As shown in Fig. 2. EVA powder was fixed on the surface of said fiber sheet (3A) which is a needle punching non-woven fabric of polyester fiber and a heat-bondable sheet having water repellency was manufactured having a dotted adhesive laver on the backside. Said heat-bondable sheet having water repellency was cut by a cutter (30) in a desirable size into a surface layer A fiber sheet as a cushion sheet of the interior was manufactured by needle punching a mixture of a polyester fiber and a polypropylene fiber (1:1 weight ratio) to S. entangle said fibers together and heating to soften said polypropylene fiber to bind said fiber together.

**Said cushion sheet was heated at 250 'C for 30 seconds to soften said polypropylene fiber and inserted in a cold press machine (31) equipped with a lower mold (32) and an upper mold (33) wherein said surface laver was put on said cushion sheet as shown in Fig. 3.

Said surface layer and said cushion sheet were pressed together by said cold press machine (31) wherein the adhesive layer of said surface layer was softened by said heated cushion sheet so that said surface layer was embossed and said surface layer and said cushion sheet were bonded together.

As above described, an interior of a trunk room of a car having an embossing design on the surface shown in Fig. 4 was manufactured.

[EXAMPLE 3] The surface layer manufactured in EXAMPLE 2 was put on a surface of a base of an interior made of a glass wool in which a thermosetting phenolic resin is impregnated and then thermoformed to manufacture an interior in which said surface laver and said base of the interior were strongly bonded together and said interior has a good moldability. Said interior can be used for a hood silencer for the engine area of a car.

[EXAMPLE 4] A heat-bondable sheet having water repellency was manufactured by using a non-woven fabric made of a mixture of an acrylic fiber and a polyester fiber (unit weight 50 g2m 2 instead of said surface layer, applying aqueous water repellent solution added with cloridated paraffin 3 by weight and antimony oxide 2 by weight as a flame retardent and said dispersion of a hot-melt adhesive powder B and C in the amount of 10 g/m 2 as solid by the same method. except for the above-mentioned applying as EXAMPLE 2.

The resulting heat-bondable sheet having water repellency was put on the surface of the glass wool in which a thermosetting phenolic resin is impregnated and thermoformed to manufacture an molded sheet having a good fire resisting property, water repellency, oil repellency and a good moldability in which said heat sensitive adhesive sheet and said glass wool were strongly bonded together.

[EXAMPLE A heat sensitive adhesive sheet was manufactured by using a non-woven fabric made of a polyester fiber and by the same method as EXAMPLE 2 excepting that said base sheet was not sucked from its backside.

A cloth without an adhesive layer was put on the surface of said heat sensitive adhesive sheet on which said dispersion of a hot-melt adhesive powder B or C was coated. Said cloth and said heat sensitive adhesive sheet were bonded together by pressing with an electric iron whose pressing face was heated at 140 After said heat pressing the surfaces of said heat sensitive adhesive sheet of the resulting laminating sheet was observed and no pimples caused by the migration of said hot-melt adhesive were recognized. After that, the 1800 peeling test of said laminating sheet was carried out and the bonding strength of each laminating sheet was 1.2 kg/cm.

y g r ^*^<lpgTM o 22 [EXAMPLE 61 parts by weight of a polyester powder having a particle size 250 mesh pass was dispersed in 60 parts by weight of water. 1 part by weight of an ethvlacrylate-methacrylic acid copolymer emulsion as a thickener and 0.001 part by weight of a fluorescence dyestuff and further 2.5 parts by weight of ammonia water were added in said dispersion by stirring to prepare a dispersion of a hot-melt adhesive powder D whose viscosity was 620 mPa -s 25 °C and pH was ,o The resulting dispersion was kept at the room temperature. Said dispersion had an excellent stability and no sedimentation was recognized after more than 4 months storage.

40 parts by weight of a polyester powder having particle size 250 mesh pass was dispersed in 60 parts by weight of water. 0.1 part by weight of a partially neutralized slightly cross-linked polyacrylic acid (Reogic 250H, Nihon Junyaku Co.) S.i as a thickener and a 0.001 part by weight of a fluorescence dyestuff and further parts by weight of ammonia water were added in said dispersion to prepare a dispersion of a hot-melt adhesive powder E whose viscosity was 1500 mPa s S'o 25 °C and pH was o The resulting dispersion was kept at the room temperature. Said dispersion has an excellent stability and no sedimentation was recognized after more than 4 months storage.

1 by weight of a dispersion of silicone water repellent was sprayed at a ratio of 120 g/m 2 on the surface of a carpet made of an acrylic fiber and a cotton fiber. While said carpet was not dried, said dispersion D or E was coated on the backside of said carpet by spraying in an amount of 60 g/m 2 as solid and said coating layer was dried by heating to form a dotted backing layer, which is a heat-bondable sheet having water repellency dotted with a hot-melt adhesive. A non-woven fabric made of polyester fiber (unit weight 15 g/m 2 was put on said backing layer of said carpet and said carpet was hot-pressed together with said non-woven fabric to manufacture a laminated carpet in which said carpet and said non-woven fabric were strongly s bonded together.

[EFFECT OF THE INVENTION] The heat-bondable sheet having water repellency of the present invention is excellent in heat sensitive adhesiveness, gas permeability and water repellency, and very useful for car components such as a head lining, door trim, a rear parcel, a trunk lining, a surface laver of an interior of a hood silencer for the engine area and the like, a backing layer of a interior base; and as padding for garments and so on.

e 9 o

Claims (6)

1. A method for manufacturing heat-bondable sheet having water repellency comprising; impregnating an aqueous water repellent solution in a fiber sheet, spraying an aqueous dispersion of a hot-melt adhesive powder having structural viscosity on said fiber sheet, and while said fiber sheet is not dried completely, adhering said hot- melt adhesive powder on the upper part of nap on the surface of said fiber sheet.

2. A method for manufacturing heat-bondable sheet having water repellency in accordance with claim 1, wherein said aqueous dispersion of said hot-melt adhesive powder is given structural viscosity by an alkali-thickening type thickener.

3. A method for manufacturing heat-bondable sheet having water repellency in accordance with claim 1 or 2, wherein a flame retardant is added in said *c:o aqueous water repellent solution and/or said aqueous dispersion of said hot-melt adhesive "0 powder. *see

4. A method for manufacturing heat-bondable sheet having water :00.0 15 repellency, substantially as hereinbefore described with reference to any one of the °oi examples but excluding the comparative examples. o,

5. A method for manufacturing heat-bondable sheet having water repellency, substantially as hereinbefore described with reference to the accompanying drawings. 20

6. A heat-bondable sheet having water repellency when manufactured by the method of any one of claims Dated 25 March, 2002 Nagoya Oilchemical Co., Ltd Patent Attorneys for the Applicant/Nominated Person SPRUSON FERGUSON [R \LIBZJ05691 do lam