CA2036125A1 - Production of cellular polyurethane moldings by sintering - Google Patents
Production of cellular polyurethane moldings by sinteringInfo
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- CA2036125A1 CA2036125A1 CA002036125A CA2036125A CA2036125A1 CA 2036125 A1 CA2036125 A1 CA 2036125A1 CA 002036125 A CA002036125 A CA 002036125A CA 2036125 A CA2036125 A CA 2036125A CA 2036125 A1 CA2036125 A1 CA 2036125A1
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- weight
- tpu
- polyurethane
- mold
- mixture
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/24—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by surface fusion and bonding of particles to form voids, e.g. sintering
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
- C08J9/06—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent
- C08J9/10—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent by a chemical blowing agent developing nitrogen, the blowing agent being a compound containing a nitrogen-to-nitrogen bond
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2375/00—Characterised by the use of polyureas or polyurethanes; Derivatives of such polymers
- C08J2375/04—Polyurethanes
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Health & Medical Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Medicinal Chemistry (AREA)
- Polymers & Plastics (AREA)
- Organic Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Polyurethanes Or Polyureas (AREA)
- Manufacture Of Porous Articles, And Recovery And Treatment Of Waste Products (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
- Treatments Of Macromolecular Shaped Articles (AREA)
- Mold Materials And Core Materials (AREA)
- Compositions Of Macromolecular Compounds (AREA)
- Molding Of Porous Articles (AREA)
- Separation, Recovery Or Treatment Of Waste Materials Containing Plastics (AREA)
Abstract
ABSTRACT OF DISCLOSURE
The present invention relates to a process for the production if cellular polyurethane moldings, preferably sheet-like materials, having a thickness of 25 mm which can have, on one or more sides, a smooth, essentially compact surface, by sintering a mixture which contains A) one or more pulverulent thermoplastic polyurethanes which expediently have a melt flow index (MFI) of from 50 to 350 at 190°C and a load of 212 N and have a Shore A hardness of from 60 to 98, and B) one or more blowing agents which are solid at 23°C, at elevated temperature, usually at from 180 to 280°C, using a mold.
The present invention relates to a process for the production if cellular polyurethane moldings, preferably sheet-like materials, having a thickness of 25 mm which can have, on one or more sides, a smooth, essentially compact surface, by sintering a mixture which contains A) one or more pulverulent thermoplastic polyurethanes which expediently have a melt flow index (MFI) of from 50 to 350 at 190°C and a load of 212 N and have a Shore A hardness of from 60 to 98, and B) one or more blowing agents which are solid at 23°C, at elevated temperature, usually at from 180 to 280°C, using a mold.
Description
203~
- 1 - o.z. OOSO/4l42s Production of cellular polYurethane moldinas by sinterina The pre~ent invention relates to a proce~s for the production of cellular polyurethane moldings, prefer-S ably polyurethane sheet-liko materials, by sinterinq a mixture which contains A~ one or more pulverulent thermoplastic poly-urethanes and B) one or more blowing agents which are solid at 23~C, at elevated temperature using a mold.
The production of cellular polyurethane moldings from microcellular polyurethane elastomers or poly-urethane foams (polyurethane is sometimes abbreviated to PU below) i~ known and is described in numerous patents and publications.
They are usually produced by introducing liquid, blowing agent-containing, pourable reaction mixtures comprising organic polyisocyanates and compounds having two or more reactive hydrogen atoms into heatable or non-heatable molds, where they are expanded and cured.
To produce PU moldings having a compact, essen-tially pore-free peripheral zone and a cellular core, QO-called structural PU foams, more of this foamable reaction mixture i~ introduced into the mold than is necessary for entirely pressure-free foam-filling of the mold cavity, i.e. the foaming is carried out in a closed mold with compression.
A review of the production of PU moldings and structural PU foams has been published, for example, in Runststoff-Handbuch, Volume 7, Polyurethane, 13t Edition, 1966, and 2nd Edition, 1983 (Carl Hanser Verlag, Munich, vienna), and in the monograph Integral~chaum~toffe, edited by Dr. H. Piechota and Dr. H. R~hr, 1975, same publishers.
Thin PU foam sheets or films, for example from 2~36i ~
- 2 - o.z. 0050/41429 0.1 to 20 mm thick, are usually produced by cuttLng large PU foam blocks or by bonding PU foam waste under pres~ure in mold~.
The abovementioned Runststoff-Handbuch, Polyurethane (2nd Edition, 1983) also describe~ the production of PU films by casting liquid PU formulations or by extruding thermoplactic polyurethsnes, abbreviated to ~PUs below.
Liquid formulations are either cast to form blocks, from which films are sliced, or the films are produced directly by centrifugal casting. TPU films in thicknesses of from 0.03 to 0.3 mm are usually produced by film blowing, and thicker films, i.e. sheets, for example up to about 3 mm, are produced by slit die extrusion. The abovementioned publications make no mention of the production of TPU films by sintering.
Use of decorative plastic films in the interior of motor vehicles is also known (R. Pfriender, Runststoffe, 76 (1986), 10, pp. 960ff), the plastic moldings being coated with films, or foam backings, pre-ferably PU foams, being produced on the films or skins.
When PU is used, the surface layers are usually produced from two-component PU system~ by in-mold coating (IMC). In this process, the mold, warmed to about 50C, 2S i8 fir~t sprayed with a release agent, and the two-component PU coating and then the PU base layer are introduced into the open mold. ~his technique for the production of component~ i8 complex and mastered by few proce~sors (Dr. N. Wachsmann, Kunststoffberater, 10/1987, page~ 27-28).
In the prior art, PVC/ABS films are usually thermoformed and then provided with a foam backing in a second process step. PVC films can be prepared by the PVC powder slush process, in which pulverulent PVC is distributed uniformly on the mold, which has been heated to approximately 250C in an oven, and the mold is then re-heated in the oven in order to gel the PVC skin.
2 a ~ ~ L 2 5 _ 3 - O.Z. 0050/41429 After the mold has been cooled, for exDmple in a water bath, the film can be removed and provided with a foam backing. The f ilms prepared by the PVC powder ~lush process are considerably cheaper than ABS/PVC, PU-IMC and TPU film3. A disadvantage of molding~ made from PVC
films with a PU foam backing is the mutually adverse effects of the PVC film and the PU foam backing. Thus, constituents, e.g. catalysts, stabilizers, inter alia, diffuse out of the PU foam into the decorative film, and, conversely, plasticizers migrate from the PVC film into the PU foam. Thesa migration processes mechanically damage the moldings, e.g. through shrinkage or embrittle-ment, and change their appearance due to di~coloration and spotting (Runststofftechnik, VDI-Verlag GmbH, Dusseldorf, 1987, Kun~tstoffe als Probleml~ser im Automo-bilbau, page~ 141ff).
It i8 an ob~ect of the present invention to produce cellular PU moldings, preferably sheet-like materials, of relatively small thickness by an in-expensive process. The PU moldings should, for certainappl$cations, expediently have a smooth, compact, es~en-tially pore-free surface on one or more sides, so that coating of the PU foam moldings with a covering or decorative film is superfluous. Any interactions between the covering film snd the PU foam which have an adverse effect on the mechanical properties of the moldings should be avoided or reduced to a minimum.
We have found that, surprisingly, these ob~ects are achieved by sintering a mixture of a solid blowing agent and TPU.
The present invention accordingly provides a proces~ for the preparation of cellular PU moldings, preferably PU sheet-like materials, which comprise~
~intering a mixture which contains or preferably comprises A) one or more pulverulent TPUs and B) one or more blowing agents which are solid at 2036~2~
_ 4 _ o.z. 0050/41429 23-C and are expediently pulverulent, at elevated temperature u~ing a mold.
The cellular PU moldings, prefer~bly PU sheet-like materials, produced by the proce~s according to the invention usually have a thickness of from 0.1 to 25 mm, preferably from 0.5 to 20 mm, in particular from 2 to 10 mm, and expediently have a smooth, compact, e3~ential-ly pore-free surface on one or both sides.
A suitable choice of TPU or a blend thereof made from a wide range of products of varying hardness and melt flow index (NFI) or softening point, these proper-tie~ being mutually dependent 80 that lower softening points cause higher melt flow indices, for example TPU
prepared using polyesterols and/or polyetherols and lS aliphatic, cycloaliphatic and/or aromatic diisocyanate~
and with addition of, for example, pigments, ~tabilizers, antioxidants or, in particular, alumina, silica gel or mixtures thereof and other auxiliaries and additives which are conventional for PU, allows cellular PU mold-ings, preferably PU ~heet-like materials, such as sheets or films, to be produced inexpensively by sintering, even in relatively small runs, in a variety of colors and with a variety of mechanical properties.
To produce PU moldings which have a smooth, 2S essentially pore-free surface on one or both side3, TPU
mixtures comprisinq TPU of various melt flow indices are expediently u~ed, an advantageous process being to first sinter the TPU or the TPU mixture having a high melt flow index in order to form the compact surface, and then to foam the TPU or TPU mixture of low melt flow index or elevated softening point in the presence of the solid blowinq agent with simultaneous sintering.
A. To produce the cellular PU moldings by the process according to the invention, one or more TPUs (A) which preferably have a melt flow index (MFI) of from 50 to 350, in particular from 100 to 300, at l90-C and a load of 212 N (21.6 kp) and a Shore A
-2Q~12~
- 5 - O.Z. 0050/41429 hardne-s of from 60 to 98, in particular from 80 to 95, are advantageously used.
TPUs ~A) having melt flow indlces and hardnesses in this range conform to the prior art and can be prep~red by reacting a) an organic and/or modified organic diisocyanate with b) a polyhydroxyl compound, preferably an essential-ly linear polyhydroxyl compound having a molecu-lar weight of from 500 to 8000, in particul~r a po}yalkylene glycol polyadipate having from 2 to 6 carbon atoms in the alkylene moiety and having a molecular welght of from 500 to 6000, or a hydroxyl-containing polytetraffl drofuran having a molecular weight of from 500 to 3500, and c) a diol having a molecular weight of from 60 to 400, in particular 1,4-butanediol, ~as chain extender, in the presence of d) a catalyst and, if desired, e) auxiliari-s and/or f) additIves, at elevated te~perature.
The following applies to the starting components (a) to (d) and, if used, (e) and/or (f)s ~) preferred organlc diisocyanates (a) are ali-phatic, cycloaliphatic and aromatic di-i~ocyanates. Examples which may be mentioned are aliphatic diisocyanates, such as hexamethylene 1,6-dii~ocyanate, 2-methylpentamethylene 1,5-diisocyanate, 2-ethylbutylene 1,4-diisocyanate or mixture~ of two or more of said aliphatic di-isocyanates, cycloaliphatic diisocyanates, such as isophorone diisocyanate, 1,4-cyclohexane .
.,, ~, , ' ~ :
- 2 ~ 2 ~
- 6 - O.Z. 0050~41429 diisocyanate, 1-methyl-2,4- and -2,6-cyclohexane diisocyanate and the corre~ponding isomor mix-tures, 4,4~-, 2,4~- and 2,2~-dicyclohexylmethane diisocyanates and the corresponding isomer mix-tures, and aromatic diisocyanates, such as 2,4-tolylene diisocyanate, mixtures of 2,4- and 2,6-tolylene diisocyanates, 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanates, mixture~ of 2,4~-and 4,4'-diphenylmethane diisocyanates, urethane-modified liquid 4,4'- and/or 2,4'-diphenylmethane diisocyanates, 4,4'-diisocyanato-1,2-diphenyl-ethane, mixtures of 4,4'-, 2,4'- and 2,2'-diiso-cyanato-1,2-diphenylethane, advantageously those containing 95 ~ by weight or more of 4,4~-diiso-cyanato-1,2-diphenylethane, and l,S-naphthylene diisocyanate. Preference is given to diphenyl-methane diisocyanate isomer mixtures containing more than 96 % by weight of 4,4'-diphenylmethane diisocyanate and in particular essentially pure 4,4'-diphenylmethane diisocyanate, hexamethylene 1,6-diisocyanate, isophorone diisocyanate and 4,4'- and/or 2,4'-dicyclohexylmethane diiso-cyanate.
~he organic diisocyanates may, if desired, be replaced by minor amounts, e.g. up to 3 mol %, preferably up to l mol %, based on the organic diisocyanate, of a trifunctional or poly-functional polyisocyanate, but these amounts must be limited so that thermoplastic polyurethanes are still obtsined. A larger amount of such isocyanates having a functionality of more than two is expediently compensated by also using compounds which have a functionality of less than two and contain reactive hydrogen atom~, so that excessive chemical crosslinking of the poly-urethane is avoided. Examples of isocyanates 2~fi~
- 7 - O.Z. 0050/41429 with a functional~ty of more than two are mix-tures of diphenylmethane diLsocyanate~ and polyphenyl-polymethylene polylsocyanate~, 80-called crude MDI, and liquid, i~ocyanurate-, urea-, biuret-, allophanate-, urethane- and/or carbodiimide modified 4,4'- and/or 2,4'-d~phenyl-methane diisocyanate~.
Examples of suitable monofunctional compounds which contain a reactive hydrogen atom and can al~o be used as molecular weight regulator~ are monoamine~, e~g. butylamine, dibutylamine, octylamine, ~tearylamine, N-methylstearylamine, pyrrolidone, piperidine and cyclohexylamine, and monoalcohols, e.q. butanol, amyl alcohol, 1-ethylhexanol, octanol, dodecanol, cyclohexanol and ethylene glycol monoethyl ether.
b) Preferred high-molecular-weight polyhydroxyl compounds (b) having molecular weights of from 500 to 8000 are polyetherols and in particular polye~terols. However, other hydroxyl-containing polymerQ having ether or e3ter group3 as bridging member~, for example polyacetals, such as poly-oxymethylenes and in particular water-insoluble formal~, e.g. polybutanediol formal and poly-hexanediol formal, and polycarbonate~, in par-ticular those made from diphenyl carbonate and 1,6-hexanediol, prepared, for example, by trans-esterification, are also suitable. The poly-hydroxyl compounds mu~t be at least substantially linear, i.e. must have a difunctional structure as far as the isocyanate reaction iB concerned.
Sa$d polyhydroxyl compounds can be u~ed as individual components or in the form of mixtures.
Suitable polyetherols can be prepared by - 8 - o.z. 0050/~1~4~
conventional proces~e~, for example by anionic polymer~zat~on using alkali metal hydroxides, such as ~odium hydroxide or pota~sium hydroxide, or alkali metal alkoxide~, such as ~odium meth-oxide, sodium ethoxide, potassium ethoxide or potassium isopropoxide, ss catalysts and with addition of one or more initiator molecules containing 2 or 3, preferably 2, reactive hydro-gen atoms in bound form, or by cationic poly-merization using Lewi acids, ~uch as antimony pentachloride, boron fluoride etherate, inter alia, or bleaching earth as catalysts, from one or more alkylene oxides having from 2 to 4 carbon atoms in the alkylene moiety.
Examples of preferred alkylene oxides are tetra-hydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide and in particular ethylene oxide and 1,2-propylene oxide. The alkylene oxides may be used individually, alternately one after the other or as mixtures. Examples of suitable initiator molecules are water, organic di-carboxylic acids, ~uch as succinic acid, adipic acid andJor glutaric acid, alkanolamines, e.g.
ethanolamine, N-alkylalkanolamines, N-alkyl-dialkanolamines, e.g. N-methyl- and N-ethyl-diethanolamine, and preferably dihydric alcohols possibly containing ether bridges in bonded form, e.g. ethanediol, 1,2- and 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, 2-methyl-1,5-pentanediol and 2-ethyl-1,4-butanediol. The initiator molecules may be employed individually or a~ mixture~.
Preference i~ given to polyetherols made from 1,2-propylene oxide and ethylene oxide in which 2 ~ 3 5 ~
_ g _ o.Z. 0050/41429 more thsn 50 ~, preferably from 60 to 80 %, of the OH qroups are primary hydroxyl groups and in which at least some of the ethylene oxide is ~n the form of a terminal block. Polyetherols of this type can be obtained, for example, by first polymerizing the 1,2-propylene oxide and then the ethylene oxide on the initiator molecule or first copolymerizing all the 1,2-propylane oxide in a mixture with some of the ethylene oxide and then polymerizing on the remainder of the ethylene oxide, or first polymerizing ~om~ of the ethylene oxide, then all the 1,2-propylene oxide and then the remainder of the ethylene oxide onto the initiator molecule.
Furthermore, hydroxyl-containing products of the polymerization of tetrahydrofuran are also very highly suitable, those having molecular weights of from 500 to 3500 being particularly preferred.
The essentially linear polyetherols have molecu-lar weights of from 500 to 8000, preferably from 600 to 6000, in particular from 800 to 3500.
They can be used either individually or in the form of mixtures with one another.
Suitable polyesterols can be prepared, for example, from dicarboxylic acids havin~ from 2 to 12, preferably from 4 to 6, carbon atoms and polyhydric alcohols. Examples of suitable dicarboxylic acids are aliphatic dicarboxylic acids, such a~ succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid and ~ebacic acid, and aromatic dicarboxylic ~cids, such as phthalic acid, isophthalic acid and tere-phthalic acid. The dicarboxylic acids can be used individually or as mixtures, for example in 2 0 3 ~ i 2 ~
- 10 - O. Z . 0050/4142g the form of a mixture of succinic acid, glut~ric ~cidAnd adipic acid. To prepare the polye~terol~, it may be ~dv~ntaseous to replace the dicar-boxylic acids by the corre~ponding dicarboxylic acid derivatives, such a~ dicarboxylic acid monoesters and/or diesters having from 1 to 4 carbon atom3 in the alcohol moiety, di-carboxylic anhydrides or dicarboxylic acid dichlorides. Examples of polyhydric alcohols are alkanediols having from 2 to 10, preferably from 2 to 6, carbon atoms and/or dialXylene ether glycols having from 4 to 12, preferably from 4 to 6, carbon atoms, such as ethylene glycol, di-ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 2,2-dimethyl-1,3-propanediol, 1,3-propanediol and dipropylene ~lycol. Depending on the desired properties, the polyhydric alcohols may be used alone or in mixtures with one another.
Also suitable are esters of carbonic acid with said alkanediols or dialkylene glycols, in particular ~hose having from 4 ~o 6 carbon atoms, such as 1,4-butanediol and/or 1,6-hexanediol, product~ of the condensation of u-hydroxy-carboxylic acids, for example w-hydroxycapric acid, and preferably products of the polymeri-zation of lactones, for example substituted or unsubstituted ~-caprolactones.
Preferred polye~terols are ethanediol poly-adipates, 1,4-butanediol polyadipates, ethanediol/1,4-butanediol polyadipates, 1,6-hexanediol/neopentyl glycol polyadipates, 1,6-hexanediol/1,4-butanediol polyadipates and polycaprolactones.
2~3~ 2~
~ O.Z. 0050/41429 The polyesterols have molecular weights of from 500 to 6000, preferably from 800 to 3500.
c) Preferred chain extender~ (c) having molecular weight~ of from 60 to 400, preferably from 60 to 300, are aliphatic diols or dialkylene glycols having from 2 to 12 carbon atoms, preferably having 2, 4 or 6 carbon atoms, e.g. ethanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol and in particular 1,4-butanediol. How-ever, diesters of terephthalic acid with glycols having from 2 to 4 carbon atoms, e.g. tere-phthalic acid bis(ethylene glycol) or bis-1,4-butanediol, and hydroxyalkylene ethers of hydroquinone, e.g. 1,4-di(~-hydroxyethyl~hydro-quinone, and polyoxytetramethylene glycols having molecular weights of from 162 to 378, are also suitable.
In order to adju3t the hardness and the melt flow index, the starting components can be varied within relatively broad molar ratios, the hard-ness and melt viscosity increasing with increas-ing content of chain extender (c), while the melt flow index decreases.
In order to prepare the TPU, the essentially difunctional polyhydroxyl compound (b) and the diol (c) are advantageously used in a molar ratio of from 1:2 to 1:6, preferably from 1:2.S to 1:4.5, so that the resultant TPU has a Shore A
hardness of from 60 to 98, preferably from 80 to 95.
d) Suitable catalysts, which, in particular, ac-celerate the reaction between the NC0 groups of the diisocyanate (a) and the hydroxyl groups of 203~
- 12 - o.z. 0050~41429 the starting component~ (b) and (c), are conventional tertiary amine~, e.g. triethylamine, dimethylcyclohexylumine, N-methylmorpholine, N, N '-dimethylpiperazine, diazabicyclot2~2~2]oc-S t~ne and sLmilar, ~nd, in particular, orgPno-metallic compounds, ~uch ~s titanates, iron compounds, tin c~mpound~, e.g. tin diacetate, tin dioctanoate, tin dilaurate and dialkyltin ~alts of aliphatic carboxylic acids, such as dibutyltin diacetate, dibutyltin dilaurate or similar. The catalyst is usually employed in an amount of from 0.001 to 0.1 part by weight per 100 parts by weight of the mixture of the polyhydroxyl com-pound (b) and the diol (c).
In addition to a catalyst, auxiliaries (e) and~or additive~ (f) may also be introduced into the starting component~. Specific examples are lubri-cants, inhibitors, hydrolyQis-, light-, heat- or dis~oloration-stabilizerR, flameproofing agents, die~, pigments, and inorganic and/or organic filler~.
To this end, the auxiliarieQ (e) and/or additives (f) may be introduced into the startîng components or into the reaction mixture for the preparation of the TPU. However, in another process variant, the auxiliaries (e) and/or additives (f) can be mixed with the TPU and subsequently melted. ~he last-mentioned method is used, in particular, to intro-duce alumina and/or silica gel and fillers, which may have a reinforcing action.
Where no further details are given on the ~uxili-aries or additives which can be used, these details can be obtained from the specialiQt literature, for example the monograph by J.H. Saunders and 2 0 ~
- 13 - O.Z. 0050/41429 K.C. Frisch, High Polymers, Volume XVI, Poly-urethane, Parts 1 and 2 (Inter~cience Publi~hers, 1962 ~nd 1964 respectively), the ~un~tstoff-Handbuch, Volume 7, Polyurethane, 1st and 2nd Edition~ ~Carl Hanser Verlaq, 1966 and 1983 re~pectively) or Germ~n Laid-Open Application DE-OS 29 01 774.
To prepare the TPU, the starting components (a), (b) and (c) are reacted in the presence of a catalyst (d) and, if used, auxiliaries (e) and/or additives (f) in such amounts that the ratio between the number of equivalents of NCO group~ of the di-isocyanate~ and the sum of the hydroxyl groups of components (b) and (c) is from 0.80 to 1.20:1, preferably from 0.95 to 1.05:1, in particular approximately 1:1.
The TPU which can be u~ed according to the invention can be prepared by the extruder process or prefer-ably by the belt proceqs by batchwi~e or continuous mixing of the starting components (a) to (d) and, if uged, (e) and/or (f), allowing the mixture to react to completion in the extruder or on a support belt at from 60 to 250C, preferably from 70 to 150C, and subsequently granulating the re~ultant TPU (A).
It may be expedient to condition the TPU obtained at from 80 to 120C, preferably from 100 to 110C, for from 1 to 24 hours before further proces~ing.
As stated above, the TPU is preferably prepared by the belt process, in which the starting components (a) to (d) and, if used, (e) and/or (f) are mixed continuously at above the melting point of the starting components (a) to ~c) using a mixing head.
The reaction mixture is applied to a support, preferably a conveyor belt, for example made of 2Q~ 2~
- 14 - o.Z. 0050~41429 metal, and pasaed through a temperature-controlled zone with a lenqth of from 1 to 20 m, preferably from 3 to 10 m, at a rate o$ from 1 to 20 m/m~nute, preferably from 4 to 10 m/minute. The reaction S temperature in this zone i8 from 60 to 200C, preferably from 80 to 180C. Depending on the dii~ocyanate content of the reaction mixture, the reaction is controlled by cooling or heating in such a manner that 90 ~ or more, preferably 98 ~ or more, of the isocyanate groups of the diisocyanates are reacted and the reaction mixture ~olidifies at the chosen temperature~ Due to the free isocyanate groups in the solidified reaction product, which make up from 0.05 to 1 % by weight, preferably from 0.1 to 0.5 ~ by weight, based on the total weight, the TPU obtained has a relatiyely low melt viscosity and a high melt flow index.
As stated above, it has proven advantageous, for example for modifying the mechanical properties of the cellular PU moldings or their light stability, and depending on the type of application, to replace one TPU by a mixture of two or more TPUs in certain amounts by weight which can be determined experimentally.
Thus, for example, black cellular moldings can be produced from TPUs based on aromatic diisocyanates, preferably 4,4'-diphenylmethane diisocyanate, and virtually any de~ired polyhydroxyl compound (b) and diol (c). Although TPU8 ba~ed on aliphatic diiso-cyanates are stable to light, they are relatively difficult to cry~tallize and are difficult to handle after proces~ing. By blending TPUs based on aromatic diisocyanates and those based on aliphatic and/or cycloaliphatic diisocyanates, the light stability of the cellular moldings can be considerably improved ~?C~1 ~r, - 15 - O.Z. 0050/41429 without the TPU mixture having any s$gnificant tendency to stlck to the mold on proces~ing. By thi~ method, TPVs prepared from aromatic ~nd all-phatic snd~or cycioaliphatic diisocyanates can give cellular molding~ having a light stability which is ~ufficient for other colors, and which, surpri~ing-ly, are essentially completely tack-free.
In a 2imilar manner, suitsble choice of TP~ made from variou~ polyhydroxyl compounds, in particular tho~e made from polyetherols or polyesterols, allows, for example, the mechanical properties of the cellular moldings, their oxidation or hydrolysi~
stability and, depending on the choice of the diisocyanate, as stated above, the light stability to be modified in a specific manner.
Soft, resilient, cellular PU moldings are produced, for example, u3ing TPU mixtures which comprise, based on 100 parts by weight, Al) from 40 to 99.S parts by weight, preferably from 60 to 85 parta by wei~ht, of a TPU ~Al), prepared uaing an aromatic diisocyanate, preferably 4,4'-diphenylmethane diisocyanate, and A2) from 0.5 to 60 parts by weight, preferably from 15 to 40 parts by weight, of a TPU (A2), prepared using an aliphatic diisocyanate, preferably s21ected from the group comprising hexamethylene 1,6-diisocyanate, isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate or a mixture of two or more of these, or a ~PU mixture which compri~es, based on 100 parts by we~ght, AI) from 60 to 99.5 parts by weight, prefer-ably from 70 to 90 parts by weight, of a 2n - 16 - O.Z. 0050/41429 TPU prepared using one or more polyoxyalkylene glycol, for example polyoxypropyleneglycol,polyoxypropylene-polyoxyethylene glycol or polyoxytetra-methylene glycol, and AII) from 0.5 to 40 parts by weight, preferably from 10 to 30 parts by weight, of a TPU
prepared using a polyesterdiol, preferably polyalkylene glycol polyadipate having from 2 to 6 carbon atom~ in the alkylene glycol moiety, and, in particular, a TPU mixture which comprises, based on 100 part-~ by weight, AlI) from 60 to 95 part~ by weight, preferably from 70 to 90 parts by weight, of a TPU
prepared using 4,4'-diphenylmethane diisocyanate and a polyoxytetramethylene glycol having a molecular weight in the ranga from 500 to 3500, and A2II) from 5 to 40 parts by weight, preferably from 10 to 30 parts by weight, of a TPU
prepared using isophorone diisocyanate and a polyesterdiol, preferably a polyalkylene glycol polyadipata having a molecular weight in the range from 800 to 3500.
The TPUs which are suitable according to the inven-tion for the production of cellular PU moldings by sintering are expediently comminuted using suitable, conventional equipment, for example a mill, and sintered at a mean grain size distribution of from 1 to 1000 pm, preferably from 50 to 800 pm, in particular from 100 to S00 ~m.
In order to improve the free-flowing properties of this TPU powder and in particular to reduce the flow of the TPU melt at vertical or overheated points of 20?~ ~5 - 17 - o. z . 0050/41429 the mold, the pulverulent TPU is expediently m~xed with pulverulent alumina or in particular pulveru-lent ~ilica gel and, if desired, a mlxture of alumina and silica gel. Even addition of only from 0.05 to 1 part by weight, preferably from 0.1 to O.3 part by weight, of alumina and/or ~ a gel, based on 100 parts by w~ight of TPU powder, pre-vented the TPU melt flowing of vertical mold surfaces during sintering or flowing away from overheated points of the mold, combined with the formation of thin areas or hole~, in particular in cellular sheet-like material~ of low thickness.
With the aid of this process variant, it i~ pos-sible, for example, to produce cellular 3heet-like lS material~ having a very uniform thickness distribution.
As ~tated above, auxiliaries and/or additives can additionally be introduced into the TPU or TPU
powder.
Examples are fillers, for example organic fillers, e.g. carbon black and melamine, and inorganic fill-ers, e.g. quartz sand, talc, amorphous silica or mixtures thereof.
~xamples of proven flameproofing agents are mela-mins, expanded graphite, polyhalobiphenyls, poly-halodiphenyl ethers, polyhalophthalic acid and derivatives thereof, polyhalooligocarbonates and polyhalopolycarbonates, the corresponding bromine compound~ being particularly effective. Other suitable flameproofing agents are phosphorus com-pounds, such as elemental phosphorus or organophos-phorus compounds. In addition, the flameproofing agents generally al~o contain a synergist, e.g.
antimony trioxide.
- 18 - O.Z. oO50/414~9 Examples of suitable oxidation retardants and hest stabilizers are halides of metals from group I of the periodic table, e.g. halides of sodium, potas-sium and lithium, alone or together with copper(I) halides, e.q. chloride~, bromide~ or iodides, sterically hindered phenol~, hydroquinones, and substituted compounds of these groups and mixtures thereof, which are preferably uæed in concentration~
of up to 1 % by weight, based on the weigh~ of the TPU ~A).
Examples of W s~abilizers are various substituted resorcinols, salicylates, benzotriazols, benzo-phenones and sterically hindered amines, which are generally employed in amounts of up to 2.0 ~ by weight, based on the weight of the TPU (A).
Mold-release agents, which are generally also added in amounts of up to 1 % by weight, based on the weight of the TPU (A), are stearic acids, stearyl alcohol, stearic acid e6ters and amides, and fatty acid esters of pentaerythritol.
Furthermore, organic dies, such as nigrosin, pig-ments, e.g. titanium dioxide, cadmium sulfide, cadmium sulfide selenide, phthalocyanines, Ultramarine Blue or carbon black, can be added.
B. To produce the cellular PU molding~, preferably PU
sheet-l$ke materials, by the process according to the invention, use i~ made of blowing agents (B) which are solid at 23C and are expediently in the form of a fine powder, for example having a mean particle ~ize of from 1 to 300 pm, preferably from S to 100 pm, in particular from 10 to 80 pm, the particle size affecting the decomposition tempera-ture and rate. The solid blowing agent is 2O~612:~J
- 19 - o.Z. 0050/41429 expediently a chemical compound which decompo~es within a cert~in, not exce~ively broad temperature range and has a high gas yield. The decomposition temperature must be mstched to tha processing temperature and to the thermal resistance of the TPU
to be foamed. These conditions can ea~ily be determined experimentally. The blowing agent must not decompo~e ~pontaneously, thu~ avoiding heat accumulation and combu~tion of the TPU. The solid blowinq agent should preferably form a homogeneous mixture with the TPU and should give decomposition products which have no health risk, have as little adverse effect as possible on the thermostability and mechanical properties of the cellular PU mold-lS ings, produce no bloom and do not cause any discoloration.
Examples of solid blowing agents which meet at least some or essentially all of these requirements are azo compounds, e.g. azobisisobutyronitrile, azo-dicarbonamide, often also called azobisformamide, or barium azodicarboxylate, hydrazines, e.g. diphenyl sulfone 3,3'-disulfohydrazide, 4,4'-oxybis(benzene-sulfohydr~zide), trihydrazinotriazine and aryl-bis(sulfohydrazide), semicarbazides, e.g. p_ tolylenesulfonylsemicarbazide or 4,4'-oxybis-(benzenesulfonylsemicarbazide), triazols, e.g. 5-morpholyl-1,2,3,4-thiatriazole, and N-nitroso compounds, e.g. N,N~-dinitrosopentamethylene-tetramine or N,N'-dimethyl-N,N'-dinitrosotere-phthalamide. Of said compounds, particular success has been achieved using the azo compounds and hydrazines, 80 that preference is given to azobis-isobutyronitrile, diphenyl sulfone 3,3'-disulfo-hydrazide, 4,4'-oxybis(benzenesulfohydrazide) and, in particular, azodicarbonamide. The solid blowing agent can be employed a~ an individual compound or 203~1 2~
- 20 - o.Z. 0050/41429 as a mixture.
The amount of blowing agent nece~ary for producing the cellular PU moldings depends, inter ali~, on the required molding geometry, the molding den~ity and thickness, and the gss yield of the blowing agent.
It is usual to use from 0.05 to 18 parts by weight, preferably from 0.1 to 10 parts by weight, in particular from 0.5 to 4 parts by weight, of one or more, preferably one, pulverulent blowing agent (B) which is solid at 23C per 100 parts by wei~ht of one or more pulverulent TPUs (A~.
To produce the cellular P~ moldings, one or more pulverulent TPUs (A) and one or more pulverulent blowing agent~ (B) are mixed homogeneously, u~ually at below 80C, preferably from 0 to 65C, using conventional mixing equipment, e.g. mixers, manu-factured by Draiswerke GmbH or the Henschel company.
The TPU/blowing agent mixture is subsequently applied in a sufficient amount with respect to the desired thickness of the cellular molding to the surface of the mold kept at from 180C to 280C, preferably from 190 to 250C, in particular from 190 to 240C, and the excess TPU/blowing agent mixture i8 removed after a short contact time, for example after from 10 to 30 second~, preferably from 16 to 25 seconds. The TPU/blowing agent powder layer adhering to the mold surface can be sintered with expansion using the heat capacity of the mold or by re-heating, for example by heating in an oven or by means of irradiation, u~ually while maintaining a relatively narrow temperature range within that mentioned above. In order to achieve specific propertie~, e.g. a cellular molding having an essentially pore-freo, smooth surface, it may be expedient to increase the surface temperature of the 20~6a2~
- 21 - o.Z. 0050/41429 mold continuously or in ~teps. This proce~ variant i8 preferred when mixtures of TPU of various melt flow indices are used, in which case, for example, a TPU of low softening point i~ first sintered to give n compact surface, and the TPU of higher softening range i8 then sintered with expansion while increasing the temperature to the de-composition range of the blowing aqent.
When the foaming and sintering process is complete, which u~ually take~ from 0.25 to 5 minutes, prefer-ably from O.S to 3 minutes, the mold is allowed to cool, for example in air, in a stream of inert gas and/or air, which may be cooled, or in a water bath, and the cellular molding formed i8 demolded within from 30 to 60 seconds.
The cellular moldings produced by ~intering, which can have one or more smooth, essentially pore-free surfaces, can, for example for technical reasons associated with procsssing or for appearance reasons, additionally be provided on one or more surfaces with a protective, decorative and/or base layer or on one or more ~urfaces with a protective or decorative layer and on the rear wi~h a base layer. The protective and decorative layer~ expedi-ently used are films, and the base layers used are reinforcing layer materisls made from plastics, which do not undergo any material-damaging inter-actions with the sintered TPU. Particularly successful protecting layers are paper or cardboard, successful decorative layers are smooth or struc-tured, colored or printed fi~ms made from TPU, and proven reinforcing base materials are molding~ made from unsaturated polyester or epoxy resins, PU
casting elastomers or TPU, with or without cellu-lose, glass fiber or carbon fiber reinforcement.
2~6~ ~
- 22 - O.Z. 0050/41429 Depend~ng on tha TPU employed, the cellular PU
moldin~s, preferably PU ~heet-like material~, produced according to the invent~on are hArd and brittle, hard and tough or preferably ~oft and resilient and have an overall density of from 0.2 to 1.0 g/cm3, preferably from 0.3 to 0.5 g/cm3, moldings containing fillers po~sibly having higher densitieq.
The moldings have good mechanical properties, in particular high tear strength, a dry, pleasant hand and are virtually free from odor.
The cellular moldings produced according to the invention are used in the engine and passenger compartments of vehicles, preferably motor vehicles, e.g. as pillar or door panelling materials, roof panelling and armrests. They are also suitable for the produ~tion of furniture, e.g. upholstered furniture, artificial leather, boot liners, e.g. for ~ki boots and hiking boots made from TPU, and luggage, e.g. briefcases and suitca~es.
Production of a beige, cellular sheet-like material A mixture prepared at room temperature, which comprised 78 parts by weight of a ~PU having a Shore A hardness of 90 and a melt flow index of 280 at 190C and a load of 212 N, and prepared by reacting 1 mol of polyoxytetramethylene glycol having a molecular weight of 1000, 4 mol of 4,4'-diphenylmethane di-isocyanate and 3 mol of 1,4-butane-diol by the belt proces4, 18 parts by weight of a TPU having a Shore A hardnes~
of 85 and a melt flow index of 180 at 190C and a load of 212 N, and prepared by reacting 1 mol of 1,4-2a~.t'?"ï
- 23 - o.z. 0050/41429 butanediol polyadipate having a molecular weight of 2000, 3 mol of isophorone dii~ocyanate and 2 mol of 1,4-butanediol by the belt process, O.7S part by weight of titanium dioxide, 3.0 part3 by weight of Sicot~n Yellow~K 2011, 0.18 part by weight of iron(II) oxide, 0.3 part by weight of Tinuvin~144 as W stabilizer and 0.3 part by weight of Irganox~1010 as oxidation ~tabilizer, was melted at 210C in a twin-screw extruder under such process conditions that the granules obtained had a Shore A hardness of 88 and a melt flow index of 310 at 190C and a load of 212 N.
The TPU granules obtained were ground using an impact disk mill to a mean grain ~ize of from 100 to 500 ~m, and 100 parts by weight thereof were mixed homogeneously at 23C with 0.15 part by weight of finely divided silica gel and 2 parts by weight of azodicarbon-amide having a mean particle size of 50 pm.
The homogeneous TPU/blowing agent/silica gel mixture was applied in a conventional manner to a mold kept at 230C, the exces~ powder mixture was removed after a contact time of 20 seconds, and the TPU/blowing agent/silica gel mixture remaining on the mold was then sintered for 2 minutes at 230C with expansion. After the mold had been cooled, in a water bath, the PU sheet-like materisl was demolded.
The cellular PU sheet-like material obtained was ~oft and resilient and had a thickness of 4 mm and a density of 0.42 g/cm3.
A mixture prepared at room temperature and comprising 72 parts by woight of a TPU having a Shore A hardness of 85 and a melt flow index of 230 2 ~ 2 ~
~ 24 - O.Z. 0050/41429 at l90-C nnd ~ load of 212 N, and prepared by reacting 1 mol of polyoxytetramethylene glycol having a molecular weight of 1000, 3.5 mol of 4,4~-diphenylmethane di-isocyanate ~nd 2.5 mol of 1,4-butanediol by the belt process, 24 parts by weight of a TPU having a Shore A hardness of 85 and a melt flow index of 180 at 190C and a load of 212 N, and prepared by reacting 1 mol of 1,4-butanediol polyadipate having a molecular weight of 2000, 3 mol of isophorone dii~ocyanate and 2 mol of 1,4-butanediol by the belt process, 0.65 part by weight of ultramarine blue, 0.24 part by weight of light yellow, 0.12 part by weight of Heliogen GreenX, 0.20 part by weight of carbon black, 0.40 part by weight of titanium dioxide, 0.79 part by weight of chalk (MicrocalcilinX), 0.8 part by weight of Irganox~1010 as oxidation ~tabilizer and 0.8 part by weight of Tinuvin~328 as W stabilizer, wa~ melted at 212C in a ZSR twin-screw extruder. The granules obtained had a Shore A hardness of 85 and a melt flow index of 220 at 190C and a load of 212 N.
The powder produced therefrom in a pin mill with addition of liquid nitrogen had a mean grain size of from 100 to 500 ~m.
To produce the cellular sheet-like material, 100 parts by weight of the TPU powder obtained were mixed homogeneously at 23C with 0.1 part by weight of a finely divided silica gel and 2.5 parts by weight of azodicarbonamide having a mean particle size of 50 ~m.
The TPU/blowing agent/silica gel mixture was 2~3~2~
- 25 - o.z~ 0050/41429 applied to a steel plate kept at 200C, the exces~ powder mixture was removed after a contact time of 30 seconds, and the TPU~blowing agent/silica gel mixture remaining on the plate wa~ then ~intered, fir t for one minute at 210-C and subsequently for 2 minutes at 230C. After the mold had cooled to about 50C in a stream of air, the PU
sheet-like material was demolded.
A soft, re~ilient, cellular PU sheet-like materi-al having a thicknes~ of 3 mm and an overall density of 0.38 g/cm3~ with a smooth, compact surface on the side facing toward the mold, was obtained.
A mixture prepared at room temperature, which comprised ~5 98 parts by weight of a TPU having a Shore A hardness of 90 and a melt flow index of 280 at 190C and a load of 212 N, and prep~red by reacting 1 mol of polyoxytetramethylene glycol having a molecular weight of 1000, 4 mol of 4,4'-diphenylmethane di-isocyanate and 3 mol of 1,4-butane-diol by the belt process, 1.0 part by weight of Special Black 4, 0.1 part by weight of iron(II) oxide tBayerferrox), 0.5 part by weight of Irganox~1010 and 0.4 p~rt by weight of Tinuvin~328, was melted at 220C in a twin-screw extruder. The granules obtained had a Shore A hardness of 91 and a melt flow index of 245 at 190C and a load of 212 N.
A powder having a mean grain size of from 100 to 500 ~m wa~ produced from the granules in the manner described in Example 1.
100 parts by weight of the TPU powder were homogeneously mixed at 23C with 1.5 parts by weight of azodicarbonamide having a mean particle size of 50 ~m.
The mixture obtained was applied to a plate-20~ 2~
- 26 - O.Z. 0050/41429 shaped mold kept at 240-C, the excess powder was removed after a contact time of 20 seconds, and the mixture remaining on the mold wa5 sintered for 2 minutes at 240-C. Aft~r the mold had been cooled in a water bath, the molding was demolded.
A cellular molding having an essentially uniform thickness of 5 mm and an overall density of 0.45 g~cm3, with a compact surface on the side facing toward the mold was obtained.
98 parts by weight of a TPU having a Shore A hardness of 85 and a melt flow index of 210 at 190C and a load of 212 N, and prepared by reacting 1 mol of butanediol adipate having a ~ole-cular weight of 2000, 3.5 mol of 4,4'-diphenylmethane diisocyanate and 2.5 mol of 1,4-butanediol by the belt process, 0.4 part by weight of titanium dioxide, 1.3 parts by weight of Sicotan Yellow g 2011 and 0.3 part by weight of Irganox~ 1010 as oxidation stabilizer were melted at 200-C in a twin-screw extruder and then granulated. The granules obtained, which had a melt flow index of 200 at l90-C and a load of 212 N, were ground to a grain ~ize distribution of from 100 to 500 ~m using a pin mill.
100 parts by weight of the powder obtained were then homogeneously mixed at 40-C in a mixer with 0.3 part by weight of finely divided silica gel and 3 parts by weight of azodicarbonamide.
This TPU/blowing agent mixture was introduced into a mold kept at 220C whose surface had previously been coated with a prefabricated film. The excess TPU/blowing agent mixture was removed after a contact time of 30 seconds. The powder layer remaining melted - 27 - O-Z. 005~4jl~
with simultaneou3 foaming due to the heat capacity of the film-coated mold.
After 2.5 minute~, the mold and the sheet-like material provided with the film were cooled to room temperature using water.
The sheet-liXe material obtained had, under the film, a soft, resilient, cellular layer having a thick-ness of 4.5 mm and a den~ity of 0.38 g/cm3.
- 1 - o.z. OOSO/4l42s Production of cellular polYurethane moldinas by sinterina The pre~ent invention relates to a proce~s for the production of cellular polyurethane moldings, prefer-S ably polyurethane sheet-liko materials, by sinterinq a mixture which contains A~ one or more pulverulent thermoplastic poly-urethanes and B) one or more blowing agents which are solid at 23~C, at elevated temperature using a mold.
The production of cellular polyurethane moldings from microcellular polyurethane elastomers or poly-urethane foams (polyurethane is sometimes abbreviated to PU below) i~ known and is described in numerous patents and publications.
They are usually produced by introducing liquid, blowing agent-containing, pourable reaction mixtures comprising organic polyisocyanates and compounds having two or more reactive hydrogen atoms into heatable or non-heatable molds, where they are expanded and cured.
To produce PU moldings having a compact, essen-tially pore-free peripheral zone and a cellular core, QO-called structural PU foams, more of this foamable reaction mixture i~ introduced into the mold than is necessary for entirely pressure-free foam-filling of the mold cavity, i.e. the foaming is carried out in a closed mold with compression.
A review of the production of PU moldings and structural PU foams has been published, for example, in Runststoff-Handbuch, Volume 7, Polyurethane, 13t Edition, 1966, and 2nd Edition, 1983 (Carl Hanser Verlag, Munich, vienna), and in the monograph Integral~chaum~toffe, edited by Dr. H. Piechota and Dr. H. R~hr, 1975, same publishers.
Thin PU foam sheets or films, for example from 2~36i ~
- 2 - o.z. 0050/41429 0.1 to 20 mm thick, are usually produced by cuttLng large PU foam blocks or by bonding PU foam waste under pres~ure in mold~.
The abovementioned Runststoff-Handbuch, Polyurethane (2nd Edition, 1983) also describe~ the production of PU films by casting liquid PU formulations or by extruding thermoplactic polyurethsnes, abbreviated to ~PUs below.
Liquid formulations are either cast to form blocks, from which films are sliced, or the films are produced directly by centrifugal casting. TPU films in thicknesses of from 0.03 to 0.3 mm are usually produced by film blowing, and thicker films, i.e. sheets, for example up to about 3 mm, are produced by slit die extrusion. The abovementioned publications make no mention of the production of TPU films by sintering.
Use of decorative plastic films in the interior of motor vehicles is also known (R. Pfriender, Runststoffe, 76 (1986), 10, pp. 960ff), the plastic moldings being coated with films, or foam backings, pre-ferably PU foams, being produced on the films or skins.
When PU is used, the surface layers are usually produced from two-component PU system~ by in-mold coating (IMC). In this process, the mold, warmed to about 50C, 2S i8 fir~t sprayed with a release agent, and the two-component PU coating and then the PU base layer are introduced into the open mold. ~his technique for the production of component~ i8 complex and mastered by few proce~sors (Dr. N. Wachsmann, Kunststoffberater, 10/1987, page~ 27-28).
In the prior art, PVC/ABS films are usually thermoformed and then provided with a foam backing in a second process step. PVC films can be prepared by the PVC powder slush process, in which pulverulent PVC is distributed uniformly on the mold, which has been heated to approximately 250C in an oven, and the mold is then re-heated in the oven in order to gel the PVC skin.
2 a ~ ~ L 2 5 _ 3 - O.Z. 0050/41429 After the mold has been cooled, for exDmple in a water bath, the film can be removed and provided with a foam backing. The f ilms prepared by the PVC powder ~lush process are considerably cheaper than ABS/PVC, PU-IMC and TPU film3. A disadvantage of molding~ made from PVC
films with a PU foam backing is the mutually adverse effects of the PVC film and the PU foam backing. Thus, constituents, e.g. catalysts, stabilizers, inter alia, diffuse out of the PU foam into the decorative film, and, conversely, plasticizers migrate from the PVC film into the PU foam. Thesa migration processes mechanically damage the moldings, e.g. through shrinkage or embrittle-ment, and change their appearance due to di~coloration and spotting (Runststofftechnik, VDI-Verlag GmbH, Dusseldorf, 1987, Kun~tstoffe als Probleml~ser im Automo-bilbau, page~ 141ff).
It i8 an ob~ect of the present invention to produce cellular PU moldings, preferably sheet-like materials, of relatively small thickness by an in-expensive process. The PU moldings should, for certainappl$cations, expediently have a smooth, compact, es~en-tially pore-free surface on one or more sides, so that coating of the PU foam moldings with a covering or decorative film is superfluous. Any interactions between the covering film snd the PU foam which have an adverse effect on the mechanical properties of the moldings should be avoided or reduced to a minimum.
We have found that, surprisingly, these ob~ects are achieved by sintering a mixture of a solid blowing agent and TPU.
The present invention accordingly provides a proces~ for the preparation of cellular PU moldings, preferably PU sheet-like materials, which comprise~
~intering a mixture which contains or preferably comprises A) one or more pulverulent TPUs and B) one or more blowing agents which are solid at 2036~2~
_ 4 _ o.z. 0050/41429 23-C and are expediently pulverulent, at elevated temperature u~ing a mold.
The cellular PU moldings, prefer~bly PU sheet-like materials, produced by the proce~s according to the invention usually have a thickness of from 0.1 to 25 mm, preferably from 0.5 to 20 mm, in particular from 2 to 10 mm, and expediently have a smooth, compact, e3~ential-ly pore-free surface on one or both sides.
A suitable choice of TPU or a blend thereof made from a wide range of products of varying hardness and melt flow index (NFI) or softening point, these proper-tie~ being mutually dependent 80 that lower softening points cause higher melt flow indices, for example TPU
prepared using polyesterols and/or polyetherols and lS aliphatic, cycloaliphatic and/or aromatic diisocyanate~
and with addition of, for example, pigments, ~tabilizers, antioxidants or, in particular, alumina, silica gel or mixtures thereof and other auxiliaries and additives which are conventional for PU, allows cellular PU mold-ings, preferably PU ~heet-like materials, such as sheets or films, to be produced inexpensively by sintering, even in relatively small runs, in a variety of colors and with a variety of mechanical properties.
To produce PU moldings which have a smooth, 2S essentially pore-free surface on one or both side3, TPU
mixtures comprisinq TPU of various melt flow indices are expediently u~ed, an advantageous process being to first sinter the TPU or the TPU mixture having a high melt flow index in order to form the compact surface, and then to foam the TPU or TPU mixture of low melt flow index or elevated softening point in the presence of the solid blowinq agent with simultaneous sintering.
A. To produce the cellular PU moldings by the process according to the invention, one or more TPUs (A) which preferably have a melt flow index (MFI) of from 50 to 350, in particular from 100 to 300, at l90-C and a load of 212 N (21.6 kp) and a Shore A
-2Q~12~
- 5 - O.Z. 0050/41429 hardne-s of from 60 to 98, in particular from 80 to 95, are advantageously used.
TPUs ~A) having melt flow indlces and hardnesses in this range conform to the prior art and can be prep~red by reacting a) an organic and/or modified organic diisocyanate with b) a polyhydroxyl compound, preferably an essential-ly linear polyhydroxyl compound having a molecu-lar weight of from 500 to 8000, in particul~r a po}yalkylene glycol polyadipate having from 2 to 6 carbon atoms in the alkylene moiety and having a molecular welght of from 500 to 6000, or a hydroxyl-containing polytetraffl drofuran having a molecular weight of from 500 to 3500, and c) a diol having a molecular weight of from 60 to 400, in particular 1,4-butanediol, ~as chain extender, in the presence of d) a catalyst and, if desired, e) auxiliari-s and/or f) additIves, at elevated te~perature.
The following applies to the starting components (a) to (d) and, if used, (e) and/or (f)s ~) preferred organlc diisocyanates (a) are ali-phatic, cycloaliphatic and aromatic di-i~ocyanates. Examples which may be mentioned are aliphatic diisocyanates, such as hexamethylene 1,6-dii~ocyanate, 2-methylpentamethylene 1,5-diisocyanate, 2-ethylbutylene 1,4-diisocyanate or mixture~ of two or more of said aliphatic di-isocyanates, cycloaliphatic diisocyanates, such as isophorone diisocyanate, 1,4-cyclohexane .
.,, ~, , ' ~ :
- 2 ~ 2 ~
- 6 - O.Z. 0050~41429 diisocyanate, 1-methyl-2,4- and -2,6-cyclohexane diisocyanate and the corre~ponding isomor mix-tures, 4,4~-, 2,4~- and 2,2~-dicyclohexylmethane diisocyanates and the corresponding isomer mix-tures, and aromatic diisocyanates, such as 2,4-tolylene diisocyanate, mixtures of 2,4- and 2,6-tolylene diisocyanates, 4,4'-, 2,4'- and 2,2'-diphenylmethane diisocyanates, mixture~ of 2,4~-and 4,4'-diphenylmethane diisocyanates, urethane-modified liquid 4,4'- and/or 2,4'-diphenylmethane diisocyanates, 4,4'-diisocyanato-1,2-diphenyl-ethane, mixtures of 4,4'-, 2,4'- and 2,2'-diiso-cyanato-1,2-diphenylethane, advantageously those containing 95 ~ by weight or more of 4,4~-diiso-cyanato-1,2-diphenylethane, and l,S-naphthylene diisocyanate. Preference is given to diphenyl-methane diisocyanate isomer mixtures containing more than 96 % by weight of 4,4'-diphenylmethane diisocyanate and in particular essentially pure 4,4'-diphenylmethane diisocyanate, hexamethylene 1,6-diisocyanate, isophorone diisocyanate and 4,4'- and/or 2,4'-dicyclohexylmethane diiso-cyanate.
~he organic diisocyanates may, if desired, be replaced by minor amounts, e.g. up to 3 mol %, preferably up to l mol %, based on the organic diisocyanate, of a trifunctional or poly-functional polyisocyanate, but these amounts must be limited so that thermoplastic polyurethanes are still obtsined. A larger amount of such isocyanates having a functionality of more than two is expediently compensated by also using compounds which have a functionality of less than two and contain reactive hydrogen atom~, so that excessive chemical crosslinking of the poly-urethane is avoided. Examples of isocyanates 2~fi~
- 7 - O.Z. 0050/41429 with a functional~ty of more than two are mix-tures of diphenylmethane diLsocyanate~ and polyphenyl-polymethylene polylsocyanate~, 80-called crude MDI, and liquid, i~ocyanurate-, urea-, biuret-, allophanate-, urethane- and/or carbodiimide modified 4,4'- and/or 2,4'-d~phenyl-methane diisocyanate~.
Examples of suitable monofunctional compounds which contain a reactive hydrogen atom and can al~o be used as molecular weight regulator~ are monoamine~, e~g. butylamine, dibutylamine, octylamine, ~tearylamine, N-methylstearylamine, pyrrolidone, piperidine and cyclohexylamine, and monoalcohols, e.q. butanol, amyl alcohol, 1-ethylhexanol, octanol, dodecanol, cyclohexanol and ethylene glycol monoethyl ether.
b) Preferred high-molecular-weight polyhydroxyl compounds (b) having molecular weights of from 500 to 8000 are polyetherols and in particular polye~terols. However, other hydroxyl-containing polymerQ having ether or e3ter group3 as bridging member~, for example polyacetals, such as poly-oxymethylenes and in particular water-insoluble formal~, e.g. polybutanediol formal and poly-hexanediol formal, and polycarbonate~, in par-ticular those made from diphenyl carbonate and 1,6-hexanediol, prepared, for example, by trans-esterification, are also suitable. The poly-hydroxyl compounds mu~t be at least substantially linear, i.e. must have a difunctional structure as far as the isocyanate reaction iB concerned.
Sa$d polyhydroxyl compounds can be u~ed as individual components or in the form of mixtures.
Suitable polyetherols can be prepared by - 8 - o.z. 0050/~1~4~
conventional proces~e~, for example by anionic polymer~zat~on using alkali metal hydroxides, such as ~odium hydroxide or pota~sium hydroxide, or alkali metal alkoxide~, such as ~odium meth-oxide, sodium ethoxide, potassium ethoxide or potassium isopropoxide, ss catalysts and with addition of one or more initiator molecules containing 2 or 3, preferably 2, reactive hydro-gen atoms in bound form, or by cationic poly-merization using Lewi acids, ~uch as antimony pentachloride, boron fluoride etherate, inter alia, or bleaching earth as catalysts, from one or more alkylene oxides having from 2 to 4 carbon atoms in the alkylene moiety.
Examples of preferred alkylene oxides are tetra-hydrofuran, 1,3-propylene oxide, 1,2- or 2,3-butylene oxide and in particular ethylene oxide and 1,2-propylene oxide. The alkylene oxides may be used individually, alternately one after the other or as mixtures. Examples of suitable initiator molecules are water, organic di-carboxylic acids, ~uch as succinic acid, adipic acid andJor glutaric acid, alkanolamines, e.g.
ethanolamine, N-alkylalkanolamines, N-alkyl-dialkanolamines, e.g. N-methyl- and N-ethyl-diethanolamine, and preferably dihydric alcohols possibly containing ether bridges in bonded form, e.g. ethanediol, 1,2- and 1,3-propanediol, 1,4-butanediol, diethylene glycol, 1,5-pentanediol, 1,6-hexanediol, dipropylene glycol, 2-methyl-1,5-pentanediol and 2-ethyl-1,4-butanediol. The initiator molecules may be employed individually or a~ mixture~.
Preference i~ given to polyetherols made from 1,2-propylene oxide and ethylene oxide in which 2 ~ 3 5 ~
_ g _ o.Z. 0050/41429 more thsn 50 ~, preferably from 60 to 80 %, of the OH qroups are primary hydroxyl groups and in which at least some of the ethylene oxide is ~n the form of a terminal block. Polyetherols of this type can be obtained, for example, by first polymerizing the 1,2-propylene oxide and then the ethylene oxide on the initiator molecule or first copolymerizing all the 1,2-propylane oxide in a mixture with some of the ethylene oxide and then polymerizing on the remainder of the ethylene oxide, or first polymerizing ~om~ of the ethylene oxide, then all the 1,2-propylene oxide and then the remainder of the ethylene oxide onto the initiator molecule.
Furthermore, hydroxyl-containing products of the polymerization of tetrahydrofuran are also very highly suitable, those having molecular weights of from 500 to 3500 being particularly preferred.
The essentially linear polyetherols have molecu-lar weights of from 500 to 8000, preferably from 600 to 6000, in particular from 800 to 3500.
They can be used either individually or in the form of mixtures with one another.
Suitable polyesterols can be prepared, for example, from dicarboxylic acids havin~ from 2 to 12, preferably from 4 to 6, carbon atoms and polyhydric alcohols. Examples of suitable dicarboxylic acids are aliphatic dicarboxylic acids, such a~ succinic acid, glutaric acid, adipic acid, suberic acid, azelaic acid and ~ebacic acid, and aromatic dicarboxylic ~cids, such as phthalic acid, isophthalic acid and tere-phthalic acid. The dicarboxylic acids can be used individually or as mixtures, for example in 2 0 3 ~ i 2 ~
- 10 - O. Z . 0050/4142g the form of a mixture of succinic acid, glut~ric ~cidAnd adipic acid. To prepare the polye~terol~, it may be ~dv~ntaseous to replace the dicar-boxylic acids by the corre~ponding dicarboxylic acid derivatives, such a~ dicarboxylic acid monoesters and/or diesters having from 1 to 4 carbon atom3 in the alcohol moiety, di-carboxylic anhydrides or dicarboxylic acid dichlorides. Examples of polyhydric alcohols are alkanediols having from 2 to 10, preferably from 2 to 6, carbon atoms and/or dialXylene ether glycols having from 4 to 12, preferably from 4 to 6, carbon atoms, such as ethylene glycol, di-ethylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,10-decanediol, 2,2-dimethyl-1,3-propanediol, 1,3-propanediol and dipropylene ~lycol. Depending on the desired properties, the polyhydric alcohols may be used alone or in mixtures with one another.
Also suitable are esters of carbonic acid with said alkanediols or dialkylene glycols, in particular ~hose having from 4 ~o 6 carbon atoms, such as 1,4-butanediol and/or 1,6-hexanediol, product~ of the condensation of u-hydroxy-carboxylic acids, for example w-hydroxycapric acid, and preferably products of the polymeri-zation of lactones, for example substituted or unsubstituted ~-caprolactones.
Preferred polye~terols are ethanediol poly-adipates, 1,4-butanediol polyadipates, ethanediol/1,4-butanediol polyadipates, 1,6-hexanediol/neopentyl glycol polyadipates, 1,6-hexanediol/1,4-butanediol polyadipates and polycaprolactones.
2~3~ 2~
~ O.Z. 0050/41429 The polyesterols have molecular weights of from 500 to 6000, preferably from 800 to 3500.
c) Preferred chain extender~ (c) having molecular weight~ of from 60 to 400, preferably from 60 to 300, are aliphatic diols or dialkylene glycols having from 2 to 12 carbon atoms, preferably having 2, 4 or 6 carbon atoms, e.g. ethanediol, 1,6-hexanediol, diethylene glycol, dipropylene glycol and in particular 1,4-butanediol. How-ever, diesters of terephthalic acid with glycols having from 2 to 4 carbon atoms, e.g. tere-phthalic acid bis(ethylene glycol) or bis-1,4-butanediol, and hydroxyalkylene ethers of hydroquinone, e.g. 1,4-di(~-hydroxyethyl~hydro-quinone, and polyoxytetramethylene glycols having molecular weights of from 162 to 378, are also suitable.
In order to adju3t the hardness and the melt flow index, the starting components can be varied within relatively broad molar ratios, the hard-ness and melt viscosity increasing with increas-ing content of chain extender (c), while the melt flow index decreases.
In order to prepare the TPU, the essentially difunctional polyhydroxyl compound (b) and the diol (c) are advantageously used in a molar ratio of from 1:2 to 1:6, preferably from 1:2.S to 1:4.5, so that the resultant TPU has a Shore A
hardness of from 60 to 98, preferably from 80 to 95.
d) Suitable catalysts, which, in particular, ac-celerate the reaction between the NC0 groups of the diisocyanate (a) and the hydroxyl groups of 203~
- 12 - o.z. 0050~41429 the starting component~ (b) and (c), are conventional tertiary amine~, e.g. triethylamine, dimethylcyclohexylumine, N-methylmorpholine, N, N '-dimethylpiperazine, diazabicyclot2~2~2]oc-S t~ne and sLmilar, ~nd, in particular, orgPno-metallic compounds, ~uch ~s titanates, iron compounds, tin c~mpound~, e.g. tin diacetate, tin dioctanoate, tin dilaurate and dialkyltin ~alts of aliphatic carboxylic acids, such as dibutyltin diacetate, dibutyltin dilaurate or similar. The catalyst is usually employed in an amount of from 0.001 to 0.1 part by weight per 100 parts by weight of the mixture of the polyhydroxyl com-pound (b) and the diol (c).
In addition to a catalyst, auxiliaries (e) and~or additive~ (f) may also be introduced into the starting component~. Specific examples are lubri-cants, inhibitors, hydrolyQis-, light-, heat- or dis~oloration-stabilizerR, flameproofing agents, die~, pigments, and inorganic and/or organic filler~.
To this end, the auxiliarieQ (e) and/or additives (f) may be introduced into the startîng components or into the reaction mixture for the preparation of the TPU. However, in another process variant, the auxiliaries (e) and/or additives (f) can be mixed with the TPU and subsequently melted. ~he last-mentioned method is used, in particular, to intro-duce alumina and/or silica gel and fillers, which may have a reinforcing action.
Where no further details are given on the ~uxili-aries or additives which can be used, these details can be obtained from the specialiQt literature, for example the monograph by J.H. Saunders and 2 0 ~
- 13 - O.Z. 0050/41429 K.C. Frisch, High Polymers, Volume XVI, Poly-urethane, Parts 1 and 2 (Inter~cience Publi~hers, 1962 ~nd 1964 respectively), the ~un~tstoff-Handbuch, Volume 7, Polyurethane, 1st and 2nd Edition~ ~Carl Hanser Verlaq, 1966 and 1983 re~pectively) or Germ~n Laid-Open Application DE-OS 29 01 774.
To prepare the TPU, the starting components (a), (b) and (c) are reacted in the presence of a catalyst (d) and, if used, auxiliaries (e) and/or additives (f) in such amounts that the ratio between the number of equivalents of NCO group~ of the di-isocyanate~ and the sum of the hydroxyl groups of components (b) and (c) is from 0.80 to 1.20:1, preferably from 0.95 to 1.05:1, in particular approximately 1:1.
The TPU which can be u~ed according to the invention can be prepared by the extruder process or prefer-ably by the belt proceqs by batchwi~e or continuous mixing of the starting components (a) to (d) and, if uged, (e) and/or (f), allowing the mixture to react to completion in the extruder or on a support belt at from 60 to 250C, preferably from 70 to 150C, and subsequently granulating the re~ultant TPU (A).
It may be expedient to condition the TPU obtained at from 80 to 120C, preferably from 100 to 110C, for from 1 to 24 hours before further proces~ing.
As stated above, the TPU is preferably prepared by the belt process, in which the starting components (a) to (d) and, if used, (e) and/or (f) are mixed continuously at above the melting point of the starting components (a) to ~c) using a mixing head.
The reaction mixture is applied to a support, preferably a conveyor belt, for example made of 2Q~ 2~
- 14 - o.Z. 0050~41429 metal, and pasaed through a temperature-controlled zone with a lenqth of from 1 to 20 m, preferably from 3 to 10 m, at a rate o$ from 1 to 20 m/m~nute, preferably from 4 to 10 m/minute. The reaction S temperature in this zone i8 from 60 to 200C, preferably from 80 to 180C. Depending on the dii~ocyanate content of the reaction mixture, the reaction is controlled by cooling or heating in such a manner that 90 ~ or more, preferably 98 ~ or more, of the isocyanate groups of the diisocyanates are reacted and the reaction mixture ~olidifies at the chosen temperature~ Due to the free isocyanate groups in the solidified reaction product, which make up from 0.05 to 1 % by weight, preferably from 0.1 to 0.5 ~ by weight, based on the total weight, the TPU obtained has a relatiyely low melt viscosity and a high melt flow index.
As stated above, it has proven advantageous, for example for modifying the mechanical properties of the cellular PU moldings or their light stability, and depending on the type of application, to replace one TPU by a mixture of two or more TPUs in certain amounts by weight which can be determined experimentally.
Thus, for example, black cellular moldings can be produced from TPUs based on aromatic diisocyanates, preferably 4,4'-diphenylmethane diisocyanate, and virtually any de~ired polyhydroxyl compound (b) and diol (c). Although TPU8 ba~ed on aliphatic diiso-cyanates are stable to light, they are relatively difficult to cry~tallize and are difficult to handle after proces~ing. By blending TPUs based on aromatic diisocyanates and those based on aliphatic and/or cycloaliphatic diisocyanates, the light stability of the cellular moldings can be considerably improved ~?C~1 ~r, - 15 - O.Z. 0050/41429 without the TPU mixture having any s$gnificant tendency to stlck to the mold on proces~ing. By thi~ method, TPVs prepared from aromatic ~nd all-phatic snd~or cycioaliphatic diisocyanates can give cellular molding~ having a light stability which is ~ufficient for other colors, and which, surpri~ing-ly, are essentially completely tack-free.
In a 2imilar manner, suitsble choice of TP~ made from variou~ polyhydroxyl compounds, in particular tho~e made from polyetherols or polyesterols, allows, for example, the mechanical properties of the cellular moldings, their oxidation or hydrolysi~
stability and, depending on the choice of the diisocyanate, as stated above, the light stability to be modified in a specific manner.
Soft, resilient, cellular PU moldings are produced, for example, u3ing TPU mixtures which comprise, based on 100 parts by weight, Al) from 40 to 99.S parts by weight, preferably from 60 to 85 parta by wei~ht, of a TPU ~Al), prepared uaing an aromatic diisocyanate, preferably 4,4'-diphenylmethane diisocyanate, and A2) from 0.5 to 60 parts by weight, preferably from 15 to 40 parts by weight, of a TPU (A2), prepared using an aliphatic diisocyanate, preferably s21ected from the group comprising hexamethylene 1,6-diisocyanate, isophorone diisocyanate and 4,4'-dicyclohexylmethane diisocyanate or a mixture of two or more of these, or a ~PU mixture which compri~es, based on 100 parts by we~ght, AI) from 60 to 99.5 parts by weight, prefer-ably from 70 to 90 parts by weight, of a 2n - 16 - O.Z. 0050/41429 TPU prepared using one or more polyoxyalkylene glycol, for example polyoxypropyleneglycol,polyoxypropylene-polyoxyethylene glycol or polyoxytetra-methylene glycol, and AII) from 0.5 to 40 parts by weight, preferably from 10 to 30 parts by weight, of a TPU
prepared using a polyesterdiol, preferably polyalkylene glycol polyadipate having from 2 to 6 carbon atom~ in the alkylene glycol moiety, and, in particular, a TPU mixture which comprises, based on 100 part-~ by weight, AlI) from 60 to 95 part~ by weight, preferably from 70 to 90 parts by weight, of a TPU
prepared using 4,4'-diphenylmethane diisocyanate and a polyoxytetramethylene glycol having a molecular weight in the ranga from 500 to 3500, and A2II) from 5 to 40 parts by weight, preferably from 10 to 30 parts by weight, of a TPU
prepared using isophorone diisocyanate and a polyesterdiol, preferably a polyalkylene glycol polyadipata having a molecular weight in the range from 800 to 3500.
The TPUs which are suitable according to the inven-tion for the production of cellular PU moldings by sintering are expediently comminuted using suitable, conventional equipment, for example a mill, and sintered at a mean grain size distribution of from 1 to 1000 pm, preferably from 50 to 800 pm, in particular from 100 to S00 ~m.
In order to improve the free-flowing properties of this TPU powder and in particular to reduce the flow of the TPU melt at vertical or overheated points of 20?~ ~5 - 17 - o. z . 0050/41429 the mold, the pulverulent TPU is expediently m~xed with pulverulent alumina or in particular pulveru-lent ~ilica gel and, if desired, a mlxture of alumina and silica gel. Even addition of only from 0.05 to 1 part by weight, preferably from 0.1 to O.3 part by weight, of alumina and/or ~ a gel, based on 100 parts by w~ight of TPU powder, pre-vented the TPU melt flowing of vertical mold surfaces during sintering or flowing away from overheated points of the mold, combined with the formation of thin areas or hole~, in particular in cellular sheet-like material~ of low thickness.
With the aid of this process variant, it i~ pos-sible, for example, to produce cellular 3heet-like lS material~ having a very uniform thickness distribution.
As ~tated above, auxiliaries and/or additives can additionally be introduced into the TPU or TPU
powder.
Examples are fillers, for example organic fillers, e.g. carbon black and melamine, and inorganic fill-ers, e.g. quartz sand, talc, amorphous silica or mixtures thereof.
~xamples of proven flameproofing agents are mela-mins, expanded graphite, polyhalobiphenyls, poly-halodiphenyl ethers, polyhalophthalic acid and derivatives thereof, polyhalooligocarbonates and polyhalopolycarbonates, the corresponding bromine compound~ being particularly effective. Other suitable flameproofing agents are phosphorus com-pounds, such as elemental phosphorus or organophos-phorus compounds. In addition, the flameproofing agents generally al~o contain a synergist, e.g.
antimony trioxide.
- 18 - O.Z. oO50/414~9 Examples of suitable oxidation retardants and hest stabilizers are halides of metals from group I of the periodic table, e.g. halides of sodium, potas-sium and lithium, alone or together with copper(I) halides, e.q. chloride~, bromide~ or iodides, sterically hindered phenol~, hydroquinones, and substituted compounds of these groups and mixtures thereof, which are preferably uæed in concentration~
of up to 1 % by weight, based on the weigh~ of the TPU ~A).
Examples of W s~abilizers are various substituted resorcinols, salicylates, benzotriazols, benzo-phenones and sterically hindered amines, which are generally employed in amounts of up to 2.0 ~ by weight, based on the weight of the TPU (A).
Mold-release agents, which are generally also added in amounts of up to 1 % by weight, based on the weight of the TPU (A), are stearic acids, stearyl alcohol, stearic acid e6ters and amides, and fatty acid esters of pentaerythritol.
Furthermore, organic dies, such as nigrosin, pig-ments, e.g. titanium dioxide, cadmium sulfide, cadmium sulfide selenide, phthalocyanines, Ultramarine Blue or carbon black, can be added.
B. To produce the cellular PU molding~, preferably PU
sheet-l$ke materials, by the process according to the invention, use i~ made of blowing agents (B) which are solid at 23C and are expediently in the form of a fine powder, for example having a mean particle ~ize of from 1 to 300 pm, preferably from S to 100 pm, in particular from 10 to 80 pm, the particle size affecting the decomposition tempera-ture and rate. The solid blowing agent is 2O~612:~J
- 19 - o.Z. 0050/41429 expediently a chemical compound which decompo~es within a cert~in, not exce~ively broad temperature range and has a high gas yield. The decomposition temperature must be mstched to tha processing temperature and to the thermal resistance of the TPU
to be foamed. These conditions can ea~ily be determined experimentally. The blowing agent must not decompo~e ~pontaneously, thu~ avoiding heat accumulation and combu~tion of the TPU. The solid blowinq agent should preferably form a homogeneous mixture with the TPU and should give decomposition products which have no health risk, have as little adverse effect as possible on the thermostability and mechanical properties of the cellular PU mold-lS ings, produce no bloom and do not cause any discoloration.
Examples of solid blowing agents which meet at least some or essentially all of these requirements are azo compounds, e.g. azobisisobutyronitrile, azo-dicarbonamide, often also called azobisformamide, or barium azodicarboxylate, hydrazines, e.g. diphenyl sulfone 3,3'-disulfohydrazide, 4,4'-oxybis(benzene-sulfohydr~zide), trihydrazinotriazine and aryl-bis(sulfohydrazide), semicarbazides, e.g. p_ tolylenesulfonylsemicarbazide or 4,4'-oxybis-(benzenesulfonylsemicarbazide), triazols, e.g. 5-morpholyl-1,2,3,4-thiatriazole, and N-nitroso compounds, e.g. N,N~-dinitrosopentamethylene-tetramine or N,N'-dimethyl-N,N'-dinitrosotere-phthalamide. Of said compounds, particular success has been achieved using the azo compounds and hydrazines, 80 that preference is given to azobis-isobutyronitrile, diphenyl sulfone 3,3'-disulfo-hydrazide, 4,4'-oxybis(benzenesulfohydrazide) and, in particular, azodicarbonamide. The solid blowing agent can be employed a~ an individual compound or 203~1 2~
- 20 - o.Z. 0050/41429 as a mixture.
The amount of blowing agent nece~ary for producing the cellular PU moldings depends, inter ali~, on the required molding geometry, the molding den~ity and thickness, and the gss yield of the blowing agent.
It is usual to use from 0.05 to 18 parts by weight, preferably from 0.1 to 10 parts by weight, in particular from 0.5 to 4 parts by weight, of one or more, preferably one, pulverulent blowing agent (B) which is solid at 23C per 100 parts by wei~ht of one or more pulverulent TPUs (A~.
To produce the cellular P~ moldings, one or more pulverulent TPUs (A) and one or more pulverulent blowing agent~ (B) are mixed homogeneously, u~ually at below 80C, preferably from 0 to 65C, using conventional mixing equipment, e.g. mixers, manu-factured by Draiswerke GmbH or the Henschel company.
The TPU/blowing agent mixture is subsequently applied in a sufficient amount with respect to the desired thickness of the cellular molding to the surface of the mold kept at from 180C to 280C, preferably from 190 to 250C, in particular from 190 to 240C, and the excess TPU/blowing agent mixture i8 removed after a short contact time, for example after from 10 to 30 second~, preferably from 16 to 25 seconds. The TPU/blowing agent powder layer adhering to the mold surface can be sintered with expansion using the heat capacity of the mold or by re-heating, for example by heating in an oven or by means of irradiation, u~ually while maintaining a relatively narrow temperature range within that mentioned above. In order to achieve specific propertie~, e.g. a cellular molding having an essentially pore-freo, smooth surface, it may be expedient to increase the surface temperature of the 20~6a2~
- 21 - o.Z. 0050/41429 mold continuously or in ~teps. This proce~ variant i8 preferred when mixtures of TPU of various melt flow indices are used, in which case, for example, a TPU of low softening point i~ first sintered to give n compact surface, and the TPU of higher softening range i8 then sintered with expansion while increasing the temperature to the de-composition range of the blowing aqent.
When the foaming and sintering process is complete, which u~ually take~ from 0.25 to 5 minutes, prefer-ably from O.S to 3 minutes, the mold is allowed to cool, for example in air, in a stream of inert gas and/or air, which may be cooled, or in a water bath, and the cellular molding formed i8 demolded within from 30 to 60 seconds.
The cellular moldings produced by ~intering, which can have one or more smooth, essentially pore-free surfaces, can, for example for technical reasons associated with procsssing or for appearance reasons, additionally be provided on one or more surfaces with a protective, decorative and/or base layer or on one or more ~urfaces with a protective or decorative layer and on the rear wi~h a base layer. The protective and decorative layer~ expedi-ently used are films, and the base layers used are reinforcing layer materisls made from plastics, which do not undergo any material-damaging inter-actions with the sintered TPU. Particularly successful protecting layers are paper or cardboard, successful decorative layers are smooth or struc-tured, colored or printed fi~ms made from TPU, and proven reinforcing base materials are molding~ made from unsaturated polyester or epoxy resins, PU
casting elastomers or TPU, with or without cellu-lose, glass fiber or carbon fiber reinforcement.
2~6~ ~
- 22 - O.Z. 0050/41429 Depend~ng on tha TPU employed, the cellular PU
moldin~s, preferably PU ~heet-like material~, produced according to the invent~on are hArd and brittle, hard and tough or preferably ~oft and resilient and have an overall density of from 0.2 to 1.0 g/cm3, preferably from 0.3 to 0.5 g/cm3, moldings containing fillers po~sibly having higher densitieq.
The moldings have good mechanical properties, in particular high tear strength, a dry, pleasant hand and are virtually free from odor.
The cellular moldings produced according to the invention are used in the engine and passenger compartments of vehicles, preferably motor vehicles, e.g. as pillar or door panelling materials, roof panelling and armrests. They are also suitable for the produ~tion of furniture, e.g. upholstered furniture, artificial leather, boot liners, e.g. for ~ki boots and hiking boots made from TPU, and luggage, e.g. briefcases and suitca~es.
Production of a beige, cellular sheet-like material A mixture prepared at room temperature, which comprised 78 parts by weight of a ~PU having a Shore A hardness of 90 and a melt flow index of 280 at 190C and a load of 212 N, and prepared by reacting 1 mol of polyoxytetramethylene glycol having a molecular weight of 1000, 4 mol of 4,4'-diphenylmethane di-isocyanate and 3 mol of 1,4-butane-diol by the belt proces4, 18 parts by weight of a TPU having a Shore A hardnes~
of 85 and a melt flow index of 180 at 190C and a load of 212 N, and prepared by reacting 1 mol of 1,4-2a~.t'?"ï
- 23 - o.z. 0050/41429 butanediol polyadipate having a molecular weight of 2000, 3 mol of isophorone dii~ocyanate and 2 mol of 1,4-butanediol by the belt process, O.7S part by weight of titanium dioxide, 3.0 part3 by weight of Sicot~n Yellow~K 2011, 0.18 part by weight of iron(II) oxide, 0.3 part by weight of Tinuvin~144 as W stabilizer and 0.3 part by weight of Irganox~1010 as oxidation ~tabilizer, was melted at 210C in a twin-screw extruder under such process conditions that the granules obtained had a Shore A hardness of 88 and a melt flow index of 310 at 190C and a load of 212 N.
The TPU granules obtained were ground using an impact disk mill to a mean grain ~ize of from 100 to 500 ~m, and 100 parts by weight thereof were mixed homogeneously at 23C with 0.15 part by weight of finely divided silica gel and 2 parts by weight of azodicarbon-amide having a mean particle size of 50 pm.
The homogeneous TPU/blowing agent/silica gel mixture was applied in a conventional manner to a mold kept at 230C, the exces~ powder mixture was removed after a contact time of 20 seconds, and the TPU/blowing agent/silica gel mixture remaining on the mold was then sintered for 2 minutes at 230C with expansion. After the mold had been cooled, in a water bath, the PU sheet-like materisl was demolded.
The cellular PU sheet-like material obtained was ~oft and resilient and had a thickness of 4 mm and a density of 0.42 g/cm3.
A mixture prepared at room temperature and comprising 72 parts by woight of a TPU having a Shore A hardness of 85 and a melt flow index of 230 2 ~ 2 ~
~ 24 - O.Z. 0050/41429 at l90-C nnd ~ load of 212 N, and prepared by reacting 1 mol of polyoxytetramethylene glycol having a molecular weight of 1000, 3.5 mol of 4,4~-diphenylmethane di-isocyanate ~nd 2.5 mol of 1,4-butanediol by the belt process, 24 parts by weight of a TPU having a Shore A hardness of 85 and a melt flow index of 180 at 190C and a load of 212 N, and prepared by reacting 1 mol of 1,4-butanediol polyadipate having a molecular weight of 2000, 3 mol of isophorone dii~ocyanate and 2 mol of 1,4-butanediol by the belt process, 0.65 part by weight of ultramarine blue, 0.24 part by weight of light yellow, 0.12 part by weight of Heliogen GreenX, 0.20 part by weight of carbon black, 0.40 part by weight of titanium dioxide, 0.79 part by weight of chalk (MicrocalcilinX), 0.8 part by weight of Irganox~1010 as oxidation ~tabilizer and 0.8 part by weight of Tinuvin~328 as W stabilizer, wa~ melted at 212C in a ZSR twin-screw extruder. The granules obtained had a Shore A hardness of 85 and a melt flow index of 220 at 190C and a load of 212 N.
The powder produced therefrom in a pin mill with addition of liquid nitrogen had a mean grain size of from 100 to 500 ~m.
To produce the cellular sheet-like material, 100 parts by weight of the TPU powder obtained were mixed homogeneously at 23C with 0.1 part by weight of a finely divided silica gel and 2.5 parts by weight of azodicarbonamide having a mean particle size of 50 ~m.
The TPU/blowing agent/silica gel mixture was 2~3~2~
- 25 - o.z~ 0050/41429 applied to a steel plate kept at 200C, the exces~ powder mixture was removed after a contact time of 30 seconds, and the TPU~blowing agent/silica gel mixture remaining on the plate wa~ then ~intered, fir t for one minute at 210-C and subsequently for 2 minutes at 230C. After the mold had cooled to about 50C in a stream of air, the PU
sheet-like material was demolded.
A soft, re~ilient, cellular PU sheet-like materi-al having a thicknes~ of 3 mm and an overall density of 0.38 g/cm3~ with a smooth, compact surface on the side facing toward the mold, was obtained.
A mixture prepared at room temperature, which comprised ~5 98 parts by weight of a TPU having a Shore A hardness of 90 and a melt flow index of 280 at 190C and a load of 212 N, and prep~red by reacting 1 mol of polyoxytetramethylene glycol having a molecular weight of 1000, 4 mol of 4,4'-diphenylmethane di-isocyanate and 3 mol of 1,4-butane-diol by the belt process, 1.0 part by weight of Special Black 4, 0.1 part by weight of iron(II) oxide tBayerferrox), 0.5 part by weight of Irganox~1010 and 0.4 p~rt by weight of Tinuvin~328, was melted at 220C in a twin-screw extruder. The granules obtained had a Shore A hardness of 91 and a melt flow index of 245 at 190C and a load of 212 N.
A powder having a mean grain size of from 100 to 500 ~m wa~ produced from the granules in the manner described in Example 1.
100 parts by weight of the TPU powder were homogeneously mixed at 23C with 1.5 parts by weight of azodicarbonamide having a mean particle size of 50 ~m.
The mixture obtained was applied to a plate-20~ 2~
- 26 - O.Z. 0050/41429 shaped mold kept at 240-C, the excess powder was removed after a contact time of 20 seconds, and the mixture remaining on the mold wa5 sintered for 2 minutes at 240-C. Aft~r the mold had been cooled in a water bath, the molding was demolded.
A cellular molding having an essentially uniform thickness of 5 mm and an overall density of 0.45 g~cm3, with a compact surface on the side facing toward the mold was obtained.
98 parts by weight of a TPU having a Shore A hardness of 85 and a melt flow index of 210 at 190C and a load of 212 N, and prepared by reacting 1 mol of butanediol adipate having a ~ole-cular weight of 2000, 3.5 mol of 4,4'-diphenylmethane diisocyanate and 2.5 mol of 1,4-butanediol by the belt process, 0.4 part by weight of titanium dioxide, 1.3 parts by weight of Sicotan Yellow g 2011 and 0.3 part by weight of Irganox~ 1010 as oxidation stabilizer were melted at 200-C in a twin-screw extruder and then granulated. The granules obtained, which had a melt flow index of 200 at l90-C and a load of 212 N, were ground to a grain ~ize distribution of from 100 to 500 ~m using a pin mill.
100 parts by weight of the powder obtained were then homogeneously mixed at 40-C in a mixer with 0.3 part by weight of finely divided silica gel and 3 parts by weight of azodicarbonamide.
This TPU/blowing agent mixture was introduced into a mold kept at 220C whose surface had previously been coated with a prefabricated film. The excess TPU/blowing agent mixture was removed after a contact time of 30 seconds. The powder layer remaining melted - 27 - O-Z. 005~4jl~
with simultaneou3 foaming due to the heat capacity of the film-coated mold.
After 2.5 minute~, the mold and the sheet-like material provided with the film were cooled to room temperature using water.
The sheet-liXe material obtained had, under the film, a soft, resilient, cellular layer having a thick-ness of 4.5 mm and a den~ity of 0.38 g/cm3.
Claims (10)
1. A process for the production of cellular polyurethane moldings, preferably polyurethane sheet-like materials, which comprises sintering a mixture which contains A) one or more pulverulent, thermoplastic polyurethanes; and B) one ore more blowing agents which are solid at 23°C, at elevated temperature using a mold.
2. A process as claimed in claim 1, wherein the polyurethane molding, preferably the polyurethane sheetlike material, is produced in one step and has, on one or more sides, a smooth, essentially pore-free surface.
3. A process claimed in claim 1 wherein the polyurethane sheet-like material has a thickness of from 0.2 to 25 mm.
4. A process as claimed in claim 1 wherein the thermoplastic polyurethane (A) has a melt flow index (MFI) of from 50 to 350 at 190°C and a load of 212 N (21.6 kp), and has a Shore A hardness of from 60 to 98.
5. A process as claimed in claim 1 wherein the thermoplastic polyurethane has a mean particle size of from 1 to 1000 µm.
6. A process as claimed in claim 1 wherein the blowing agent comprises pulverulent azobisisobutyronitrile, azodicarbonamide, diphenyl sulfone 3,3'-disulfohydrazide or 4,4'-oxybis(benzene-sulfohydrazide).
7. A process as claimed in claim 1, wherein the mixture contains from 0.05 to 18 parts by weight of one or more pulverulent blowing agents (B) which are solid at 23°C per 100 parts by weight of the pulverulent thermoplastic polyurethane (A).
8. A process as claimed in claim 1, wherein the sintering is carried out in the presence of from 0.05 to 1 part by weight of aluminum oxide and/or silica gel per 100 parts by weight of the thermoplastic polyurethane.
9. A process as claimed in claim 1, wherein the thermoplastic polyurethane (A) is prepared by reacting a) an organic, preferably aromatic and/or cycloaliphatic diisocyanate with b) an essentially linear polyhydroxyl compound having a molecular weight of from 500 to 8000, perferably a polyalkylene glycol polyadipate having from 2 to 6 carbon atoms in the alkylene moiety and a molecular weight of from 500 to 6000, or a hydroxyl-containing polytetrahydrofuran having a molecular weight of from 500 to 3500, and c) a diol having a molecular weight of from 60 to 400, preferably 1,4-butanediol, in a ratio between the number of equivalents of NCO groups of the organic diisocyanate (a) to the sum of the hydroxyl groups of components (b) and (c) of from 0.8:1.0 to 1.2:1.0, by the extruder process or preferably by the belt process.
10. A process as claimed in claim 1, wherein the mold is at from 180 to 280°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4006648A DE4006648A1 (en) | 1990-03-03 | 1990-03-03 | METHOD FOR PRODUCING CELL-BASED POLYURETHANE MOLDED BODIES BY SINTERING |
| DEP4006648.7 | 1990-03-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2036125A1 true CA2036125A1 (en) | 1991-09-04 |
Family
ID=6401323
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002036125A Abandoned CA2036125A1 (en) | 1990-03-03 | 1991-02-11 | Production of cellular polyurethane moldings by sintering |
Country Status (6)
| Country | Link |
|---|---|
| EP (1) | EP0447817B1 (en) |
| JP (1) | JPH04218540A (en) |
| AT (1) | ATE125839T1 (en) |
| CA (1) | CA2036125A1 (en) |
| DE (2) | DE4006648A1 (en) |
| ES (1) | ES2075231T3 (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5210127A (en) * | 1991-10-28 | 1993-05-11 | Bayer Aktiengesellschaft | Free-flowing, thermoplastically processible and post-crosslinkable polyurethane powders |
| US5252617A (en) * | 1992-03-25 | 1993-10-12 | Bayer Aktiengesellschaft | Expandable polyurethane powder preparations containing blowing agents and their use for the production of foamed polyurethane moldings |
| WO2008082474A1 (en) | 2006-12-29 | 2008-07-10 | Rubberlite Incorporated | Closed cell foams comprising urethane elastomers |
| US8445556B2 (en) | 2006-12-29 | 2013-05-21 | Rubberlite, Inc. | Cellular elastomer compositions |
| US9682522B2 (en) | 2012-07-10 | 2017-06-20 | Nike, Inc. | Low density foamed article made by bead foam compression molding method |
| CN109641375A (en) * | 2016-08-25 | 2019-04-16 | 巴斯夫欧洲公司 | Microwave foaming |
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|---|---|---|---|---|
| EP0825221B1 (en) * | 1992-05-08 | 2001-07-11 | Showa Highpolymer Co., Ltd. | Polyester sheet |
| US5321052A (en) * | 1992-05-12 | 1994-06-14 | Showa Highpolymer Co., Ltd. | Polyester foamed thin materials |
| US5314927A (en) * | 1992-05-13 | 1994-05-24 | Showa Highpolymer Co., Ltd. | Polyester foamed articles and method for producing the same |
| JP2609795B2 (en) * | 1992-05-14 | 1997-05-14 | 昭和高分子株式会社 | Polyester expandable particles and foam |
| JPH11201378A (en) * | 1998-01-13 | 1999-07-30 | Mitsubishi Electric Corp | Cartridge, and vacuum heat insulation body equipped therewith |
| JP3968612B2 (en) | 1998-01-27 | 2007-08-29 | 三菱電機株式会社 | FULL VACUUM INSULATION BOX, REFRIGERATOR USING THE VACUUM VACUUM INSULATION BOX, METHOD FOR PRODUCING THE FULL VACUUM INSULATION BOX, AND METHOD OF DECOMPOSING |
| DE19942393C2 (en) * | 1999-07-15 | 2002-07-18 | Bayer Ag | Soft, elastic polyurethane films, process for their production and their use |
| JP2006233097A (en) * | 2005-02-25 | 2006-09-07 | Inoac Corp | Thermoplastic polyurethane material for powder flash molding |
| DE112007002776A5 (en) * | 2006-12-20 | 2009-11-05 | Basf Se | Anisotropic cellular elastomers |
| JP5305247B2 (en) * | 2007-12-28 | 2013-10-02 | 日本ポリウレタン工業株式会社 | Sheet-like polyurethane resin molding having a two-layer structure and method for producing the same |
| WO2010027058A1 (en) * | 2008-09-04 | 2010-03-11 | 日本ポリウレタン工業株式会社 | Expandable powdery thermoplastic polyurethane resin composition, non-expandable powdery thermoplastic polyurethane resin composition, and sheet-like polyurethane resin molded article and method for production thereof |
| JP2010059314A (en) * | 2008-09-04 | 2010-03-18 | Nippon Polyurethane Ind Co Ltd | Foaming powdery thermoplastic polyurethane resin composition, sheet-like polyurethane resin molded product having double layer structure using the same, and method for manufacturing the same |
| HUP1200268A2 (en) * | 2012-05-08 | 2013-11-28 | Ratipur Gepjarmuealkatreszt Es Autofelszerelest Gyarto Es Ertekesitoe Kft | Method for manufacturing pur integral foam with modified structure, pur integral foam with modified structure |
| JP2017179254A (en) * | 2016-03-31 | 2017-10-05 | 株式会社ジェイエスピー | Thermoplastic polyurethane foaming particles and thermoplastic polyurethane foaming particle molded body |
| EP3487677B1 (en) | 2016-07-21 | 2021-09-08 | Basf Se | Microwave welding of elastomer powder |
| DE102016223567A1 (en) | 2016-11-28 | 2018-05-30 | Adidas Ag | Process for the production of sporting goods and sporting goods |
| DE102016125876A1 (en) * | 2016-12-29 | 2018-07-05 | Technische Universität Dresden | Process for the preparation of a thermally insulating material and thermally insulating material |
| WO2019162172A1 (en) | 2018-02-20 | 2019-08-29 | Basf Se | Bonding bodies by means of thermoplastic elastomer, using high-frequency radiation |
| TWI656169B (en) * | 2018-03-16 | 2019-04-11 | 加久企業股份有限公司 | Elastic composite process and its finished products |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE973134C (en) * | 1951-04-26 | 1959-12-10 | Basf Ag | Process for the production of dimensionally stable porous moldings from thermoplastics |
| GB1007988A (en) * | 1961-09-13 | 1965-10-22 | Nat Distillers Chem Corp | Molded plastic foams |
| GB1170261A (en) * | 1966-03-23 | 1969-11-12 | Ronald Ian Kliene | Composite Plastics Materials. |
| FR2512736B1 (en) * | 1981-09-14 | 1987-11-20 | Dana Corp | METHOD FOR FORMING A SEAL AND SEAL OBTAINED |
| DE3817509A1 (en) * | 1988-05-24 | 1989-12-07 | Solvay Werke Gmbh | METHOD FOR PRODUCING SHAPED ITEMS |
-
1990
- 1990-03-03 DE DE4006648A patent/DE4006648A1/en not_active Withdrawn
-
1991
- 1991-02-11 CA CA002036125A patent/CA2036125A1/en not_active Abandoned
- 1991-02-20 DE DE59106103T patent/DE59106103D1/en not_active Expired - Lifetime
- 1991-02-20 AT AT91102375T patent/ATE125839T1/en not_active IP Right Cessation
- 1991-02-20 ES ES91102375T patent/ES2075231T3/en not_active Expired - Lifetime
- 1991-02-20 EP EP91102375A patent/EP0447817B1/en not_active Expired - Lifetime
- 1991-02-28 JP JP3034093A patent/JPH04218540A/en not_active Withdrawn
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5210127A (en) * | 1991-10-28 | 1993-05-11 | Bayer Aktiengesellschaft | Free-flowing, thermoplastically processible and post-crosslinkable polyurethane powders |
| US5252617A (en) * | 1992-03-25 | 1993-10-12 | Bayer Aktiengesellschaft | Expandable polyurethane powder preparations containing blowing agents and their use for the production of foamed polyurethane moldings |
| WO2008082474A1 (en) | 2006-12-29 | 2008-07-10 | Rubberlite Incorporated | Closed cell foams comprising urethane elastomers |
| EP2106416A1 (en) * | 2006-12-29 | 2009-10-07 | Rubberlite Incorporated | Closed cell foams comprising urethane elastomers |
| EP2106416A4 (en) * | 2006-12-29 | 2010-01-13 | Rubberlite Inc | Closed cell foams comprising urethane elastomers |
| CN101641385A (en) * | 2006-12-29 | 2010-02-03 | 鲁贝莱特公司 | The closed-cell foam that contains polyurethane elastomer |
| US8445556B2 (en) | 2006-12-29 | 2013-05-21 | Rubberlite, Inc. | Cellular elastomer compositions |
| US9682522B2 (en) | 2012-07-10 | 2017-06-20 | Nike, Inc. | Low density foamed article made by bead foam compression molding method |
| CN109641375A (en) * | 2016-08-25 | 2019-04-16 | 巴斯夫欧洲公司 | Microwave foaming |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH04218540A (en) | 1992-08-10 |
| DE59106103D1 (en) | 1995-09-07 |
| ES2075231T3 (en) | 1995-10-01 |
| ATE125839T1 (en) | 1995-08-15 |
| EP0447817A2 (en) | 1991-09-25 |
| DE4006648A1 (en) | 1991-09-05 |
| EP0447817B1 (en) | 1995-08-02 |
| EP0447817A3 (en) | 1992-03-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| FZDE | Discontinued |