CA1056083A - Quick-ripening unsaturated-polyester molding materials - Google Patents
Quick-ripening unsaturated-polyester molding materialsInfo
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- CA1056083A CA1056083A CA236,945A CA236945A CA1056083A CA 1056083 A CA1056083 A CA 1056083A CA 236945 A CA236945 A CA 236945A CA 1056083 A CA1056083 A CA 1056083A
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- unsaturated polyester
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- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/06—Unsaturated polyesters
Abstract
ABSTRACT OF THE DISCLOSURE
Curable unsaturated polyester molding materials which give high viscosities without the flow properties of the molding materials being adversely affected during processing are manufactured from a) an unsaturated polyester mixture consisting of an amorphous polyester and a crystalline polyester, b) at least one copolymerizable olefinic compound, c) an alkaline earth metal oxide and/or hydroxide, d) at least one inhibitor and e) conventional assistants and additives.
Curable unsaturated polyester molding materials which give high viscosities without the flow properties of the molding materials being adversely affected during processing are manufactured from a) an unsaturated polyester mixture consisting of an amorphous polyester and a crystalline polyester, b) at least one copolymerizable olefinic compound, c) an alkaline earth metal oxide and/or hydroxide, d) at least one inhibitor and e) conventional assistants and additives.
Description
1056~83 O.Z~ 30,881 MOLDING MATERIALS BASED ON UNSATURATED POLYESTER RESINS
The present invention relates to molding materials based on unsaturated polyester resins which contain alkaline earth metal oxides or hydroxidesg inhibitors and, optionally, conventional fillers and reinforcing agents and other additives, and wherein the unsaturated polyester consists of a mixture of an amorphous polyester and a crystalline polyester. These molding materials can, in particular, be used for the manufacture Or paper laminates.
Molding materials and press-forming materials based on unsaturated polyester resins usually contain, in accordance with their envisaged use, unsaturated polye3ters, monomeric vinyl compounds copolymerizable therewith, polymerization initiators and inhibitors, pulverulent fillers, and glass fibers or sheet-like glass fiber structures. To manufacture impregnated reactive paper laminates based on unsaturated polyester resins, rillers are generally not added, so as to obtain, after heat-curing under pressure, transparent binders or coatings through which the paper decoration is visible.
To obtain non-tacky molding materials and press-forming materials, as well as semi-rinished goods, exhibiting optimum flow under the required curing conditions, small amounts of finely particulate alkaline earth metal oxide or hydroxide are in most cases admixed with the polyester molding materials. This causes thickening through salification of the carboxyl end groups of the unsaturated poly-ester, and complex formation. The pot life or available processing timè is from one to several hours whilst the time required to reach the ultimate viscosity (thickening time) is up to several weeks. How-ever, this makes economical processing difficult since, in con-q~ , ~056083 Z . 3a 881 tinuous production, substantial numbers of moldings must be stored,which represents a disadvantage~
For rapid processing of the materials - which is, eOg., essential when using them in conveyor belt installations - the time required for thickening up should be as short as possible (with a pot life of about one hour) whilst the viscosity of the molding material or press-forming material in its final s~ate (at room temperature) should be high.
Numerous additives which accelerate the increase in viscosity Of unsaturated polyester resins containing magnesium oxide have been disclosed; most of these are polar substances. For example, a low concentration of water (German Patent 1,198,551), as well as compound which liberate water (German Published Application 2,221,108) reduce the thickening time, but give a low final viscosity, so that the resulting products are frequently tacky (cf. F.B~Alvey, J. Polym.
Sci~ 9 (1971)~ 2~233-2~245)o Furthermore, the addition of dicarboxylic acid anhydrides, eOg. hexahydrophthalic anhydride (U.S. Patent 3~465~061) ~ of carboxylic acids (German Printed Application 1~694~821 and U.S. Patent 3~465~061) ~ of phosphorous acid esters or their halides, and of sulfonic acids and sulfonic acid halides (British Patent 1~058~460) has been proposed. The effect of these thickening accelerators is, however, inadequate, in most cases, to achieve rapid ripening which should require only a few minutes. If brief thickening times are achieved by adding a larger amount of accelerator, the resulting viscosity of the molding material or press-forming material i9 relatively low, and the materials remain tacky so that the release films can only be pulled off with difficulty, if at all, particularly when using thin unfilled resin layers, e.g. for the manufacture of reactive paper laminates. It is true that the tacki-ness can be reduced by adding fillers but this destroys the requisitetransparency of the cured molding materialsO
Other methods of thickening, e.g. the use of half-ester salts of trivalent metals (German Printed Application 1,060,590) give pot
The present invention relates to molding materials based on unsaturated polyester resins which contain alkaline earth metal oxides or hydroxidesg inhibitors and, optionally, conventional fillers and reinforcing agents and other additives, and wherein the unsaturated polyester consists of a mixture of an amorphous polyester and a crystalline polyester. These molding materials can, in particular, be used for the manufacture Or paper laminates.
Molding materials and press-forming materials based on unsaturated polyester resins usually contain, in accordance with their envisaged use, unsaturated polye3ters, monomeric vinyl compounds copolymerizable therewith, polymerization initiators and inhibitors, pulverulent fillers, and glass fibers or sheet-like glass fiber structures. To manufacture impregnated reactive paper laminates based on unsaturated polyester resins, rillers are generally not added, so as to obtain, after heat-curing under pressure, transparent binders or coatings through which the paper decoration is visible.
To obtain non-tacky molding materials and press-forming materials, as well as semi-rinished goods, exhibiting optimum flow under the required curing conditions, small amounts of finely particulate alkaline earth metal oxide or hydroxide are in most cases admixed with the polyester molding materials. This causes thickening through salification of the carboxyl end groups of the unsaturated poly-ester, and complex formation. The pot life or available processing timè is from one to several hours whilst the time required to reach the ultimate viscosity (thickening time) is up to several weeks. How-ever, this makes economical processing difficult since, in con-q~ , ~056083 Z . 3a 881 tinuous production, substantial numbers of moldings must be stored,which represents a disadvantage~
For rapid processing of the materials - which is, eOg., essential when using them in conveyor belt installations - the time required for thickening up should be as short as possible (with a pot life of about one hour) whilst the viscosity of the molding material or press-forming material in its final s~ate (at room temperature) should be high.
Numerous additives which accelerate the increase in viscosity Of unsaturated polyester resins containing magnesium oxide have been disclosed; most of these are polar substances. For example, a low concentration of water (German Patent 1,198,551), as well as compound which liberate water (German Published Application 2,221,108) reduce the thickening time, but give a low final viscosity, so that the resulting products are frequently tacky (cf. F.B~Alvey, J. Polym.
Sci~ 9 (1971)~ 2~233-2~245)o Furthermore, the addition of dicarboxylic acid anhydrides, eOg. hexahydrophthalic anhydride (U.S. Patent 3~465~061) ~ of carboxylic acids (German Printed Application 1~694~821 and U.S. Patent 3~465~061) ~ of phosphorous acid esters or their halides, and of sulfonic acids and sulfonic acid halides (British Patent 1~058~460) has been proposed. The effect of these thickening accelerators is, however, inadequate, in most cases, to achieve rapid ripening which should require only a few minutes. If brief thickening times are achieved by adding a larger amount of accelerator, the resulting viscosity of the molding material or press-forming material i9 relatively low, and the materials remain tacky so that the release films can only be pulled off with difficulty, if at all, particularly when using thin unfilled resin layers, e.g. for the manufacture of reactive paper laminates. It is true that the tacki-ness can be reduced by adding fillers but this destroys the requisitetransparency of the cured molding materialsO
Other methods of thickening, e.g. the use of half-ester salts of trivalent metals (German Printed Application 1,060,590) give pot
- 2 -1056083 o. z . 30,881 lives of only a few ~inutes, and therefore these systems are hardlysuitable for conventional methods of manufacture of molding materials.
The fact that phosphorus halides are excellent thickening accelerators is disclosed, inter alia, in ~erman Patent Application P 23 11 395.3 published on May 12, 1974. By use of these halides, tack-free, very viscous molding materials can be obtained very quickly;
however, the additives disclosed do not have a favorable effect on the flow during hot-pressing, as the viscosity of the materials increases, whilst such flow is important to give optimum surrace characteristics Or the moldings.
The use Or a release film is desirable to reduce the evaporation Or styrene - conventionally used as a monomer - from the resin layer and prevent the stacked paper laminates sticking to~ether on storage.
Films of polyethylene, polyamide or polyester and polyvinyl alcohol have proved satisfactory.
From a commercial point o~ view, polyethylene films would be of particular interest, but since they swell and are permeable to styrene, an~ therefore give a wavy surface of the molding material ir thickening takes place slowly, they cannot be used for certain applications, e.~. with reactive paper laminates. The other release films mentioned above are more expensive and cannot be pulled Orr conventionally thickened unrilled molding materials without difficulty;
however, in contrast to polyethylene rilms, they do prevent major losses Or styrene and virtually do not swell in this monomer.
It is an object of the present invention to provide quick-ripening molding materials which are suitable for use with these styrene-impermeable films.
It is a rurther object of the present invention to provide molding materials based on unsaturated polyester resins which, whilst having an adequate pot li~e, thicken more quickly than conventional materials and give a very high viscosity, without an adverse effect on the rlow of the molding materials durin~ processin~
1~56083 We have found that this ob~ect is achieved by unsaturated polyester molding materials, curable in the presence of conventional polymerization initiators, and based on a mixture of (a) from 15 to 80 per cent by weight, based on the total amount of the components (a) to ~e), of at least one unsaturated poly-ester, having an acid number of from 5 to 100 and a mean molecular weight of from 50a to 10 000, (b) from 5 to 60 per cent by weight, based on the mixture of components (a) and (b), of at least one copolymerizable olefinic compound (c) from 1 to 5 per cent by weight, based on the mixture of components (a) and (b), of an alXaline earth metal oxide and/or hydroxide ~d) from O.OOS to 0.1 per cent by weight, based on the mixture of components (a) and (b), of an inhibitor selected from the group consisting of hydroquinones, quinones, nitrobenzenes, aromatic amines and salts of N-nitroso-N-cyclohexyl-hydro-xylamines and (e) assistants and additives, the improvement which comprises: using as said unsaturated poly-ester (a) from 10 to 95% by weight of at least one amorphous unsaturated polyester ~al) which is soluble in component (b) at room temperature and from 90 to 5% by weight of at least one crystalline unsaturated polyester ~a2) which has a solubility of less than 30% by weight in styrene at 23C or is insoluble in component ~b) or in the mixture of (b) and (al) at room temperature.
The present invention also relates to the use of these unsaturated polyester molding materials for covering or coating a sheetlike base of organic or inorganic fibers, and to the ~manufacture o laminates therefrom.
The molding materials of the invention are cured at room temperature or above, if appropriate in the presence of thîc ~ ng accelerators~
~ 4 lOS6083 The molding materials of the invention specifically have the advantage, over conventional unsaturated polyester resin m~lding materials, that they are tack-free and dimensionally stable at room temperature and may be cured to give transparent molded products.
The following are details relating to the components of the molding materials to be used in the process of the invention:
(a) Suitable unsaturated polyesters are the conventional polyconden-sation products of polybasic, especially dibasic, carboxylic acids and their esterifiable derivatives, which are linked by ester bonds to polyhydric, especially dihydric, alcohols and optionally additionally contain radicals of mono~asic carboxylic acids and/or radicals of monohydric alcohols and/or radicals of hydroxycarboxylic acids wherein at least some of the radicals must contain ethylenic copolymerizable groups.
The polyhydric, especially dihydric, alcohols are in general reacted in stoichiometric, or approximately stoichiometric, amounts with polybasic, especially dibasic carboxylic acids or their condensable derivatives.
(al) Suitable amorphous unsaturated polyesters are the conventional unsaturated polyesterQ, soluble in monomer (b), which are manufactured by polycondensation of a,~-unsaturated dicarboxylic acids or their anhydrides, optionally in combination with mono-carboxylic acids and/or polycarboxylic acids, and monoalcohols and/or polyalcohols, which serve as modifiers; examples of a,~-unsaturated dicarboxylic acids which may be used are fumaric acid, maleic acid, mesaconic acid, itaconic acid, methyleneglutaric acid, citraconic acid and the like or their esters or anhydrides.
Maleic acid, maleic anhydride and fumaric acid are preferred.
Examples of suitable monocarboxylic acids and/or polycarboxylic acids which act as modifiers are ethylhexanoic acid, fatty aci~ds, methacrylic acid, benzoic acid, o-phthalic acid, isophthalic acid, tetrahydrophthalic acid, tetrachlorophthalic acid, èndomethylenetetrachlorophthalic acid, hexachloroendomethylenetetra-hydrophthalic acid, succinic acid, glutaric acid, adipic acid and ~ ~ - 5 ~
.... __ . ~, pimelic acid.
Suitable alcohol components are diols, e.g. 1,2-propane-diol, 1,3-butanediol, 1,3-propanediol, ethylene glycol, diethylene glycol,-polyethylene glycol, 1,6-hexanediol, neopentylglycol, - 5a -,. ~f~, ' . , ` ~056083 o. z . 30,881 propa~e monoallylether, 1,4-butanediol, vinylglycol and dipropylene glycol, with propanediol, diethylene glycol and dipropylene glycol being preferred. Minor amounts of polyalcohols, e.g. glycerol, tri-methylolpropane and pentaerythritol, and of monoalcohols, e.g.
2-ethylhexanol or ratty alcohols, may be used at the same time.
Epoxides, e.g. propylene oxide, can also be used to manufacture the unsaturated polyesters.
The polycondensation can be carried out either in the melt, or azeotropically using an inert entraining agent, e.g. xylene, or in solution. Ir an epoxide is also used, it may be desirable to use a catalyst.
The polyesters are in general manufactured so as to give acid numbèrs of from 5 to 100 and mean molecular weights of advantageously from 1,000 to 4,000. It is also possible to use mixtures of such polyesters, and mixtures with diallyl ester prepolymers, e.g. obtained e.g. obtained from diallyl phthalate.
Amorphous unsaturated polyesters soluble in the monomer (b) are to be under~tood a~ those of which at least 60 per cent by weight di~olves in styrene at 23C.
(a2) Crystalline unsaturated polyesters, sparingly soluble or insoluble in component (b) or in the mixture o~ (b) and (al), at room temperature, which may be used accordin~ to the invention are such unsaturated polye~ters as are disclosed, e.g., in British Patent 644,287, U.S. Patent 3,510,457 and German Printed Application 1,544,673. A characteristic feature of the synthesis of these unsaturated polyesters is that symmetrical diols, e.g. 1,4-butanediol, 1,3-propanediol, 1,6-hexanediol, neopentyl glycol and hydroxyp~valic acid neopentyl glycol ester, and predominantly symmetrical dicarboxy-lic acids, e.g. fumaric acid, terephthalic acid and the like, are used.
The melting range of these crystalline unsaturated polyesters is in general from 40 to 180C, preferably from 80 to 120C, depending on their structure. Mixtures of such crystalline unsaturated polyesters, the~mol~cular r ' -O.Z. 30,881 weight of which is from 300 to 10,000, advantageously from 700 to 4,000, may also be employed. They are preferably employed as crystallite suspensions of low viscosity, which are suitably obtained by slow cooling Or the hot, agitated solution of the crystallizing polyester (a2) and the amorphous unsaturated polyester (a1) in a copolymerizable vinyl monomer. It is also possible first to cool a hot solution of the crystallizing polyester (a2) in a vinyl monomer and then to combine the resulting crystallite suspension with a solution of an amorphous polyester (a1) in the monomeric vinyl com-pound.
If the crystallite suspension obtained has too high a v~scosity, the latter can be lowered to the desired value by adding further vinyl monomer or adding a solution of an amorphous unsaturated poly-èster in the vinyl monomer at room temperature.
Crystalline unsaturated polyesters which are sparingly soluble or insoluble in the monomer or in the solution of component (a1) in the monomer are to be understood as those which have a solubility of <30 per cent by wei~ht in styrene at 23C and are at least 70%
crystalline.
According to the invention, the unsaturated polyester (a) comprises preferably from 30 to 80, per cent by weight of the soluble, amorphous unsaturated polyester (al) and preferably from 15 to 60, per cent by weight of the crystalline unsaturated polyester (a2) which is sparingly soluble or insoluble at room temperature.
The molding materials according to the invention in general con-tain from 15 to 80, preferably from 20 to 70, per cent by weight of unsaturated polyester (a) based on the total amount of the com-ponents (a) to (ej.
(b) Suitable copolymerizable olefinic monomeric compounds are the vinyl and allyl compounds conventionally used to manu~acture un-saturated polyester molding materials, e.g. styrene, substituted st renes, such as p-chlorostyrene, o~-methylstyrene or vinyltoluene, ~ ~ 7 ~
1(~560~3 0,Z. 30,881 esters of acrylic and methacrylic acid ~ith alcohols containing 1 to 18 carbon atoms, e.g. methyl methacrylate, butyl acrylate, ethyl-hexyl acrylate, hydroxypropyl acrylate and dicyclopentadienyl acrylate, acrylic and methacrylic acid amides, allyl esters, e.g.
diallyl phthalate, and vinyl ester, e.g. vinyl ethylhexanoate and vinyl pivalate, and others. In addition, minor amounts of poly-olefinic compounds, e.g. divinylbenzene or butanediol diacrylate~
may al80 be present.
Mixtures of the above olefinic monomers may aiso be used. The preferred components (b) are styrene, vinyltoluene, ~-methylstyrene and diallyl phthalate. The molding materials according to the invention in general contain preferably from 15 to 40, per cent by weight of component (b), based on the mixture of components (a) and (b).
(C) Suitable alkaline earth metal oxides are calcium oxide, calcium hydroxide and, preferably, magnesium oxide, and mixtures of the8e oxides or hydroxide5. These may also be partially replaced by zinC oxide.
In general, the molding material according to the invention contains preferably from 1.5 to 2.5, per cent by weight of component (C)~ ba8ed on the mixture of components (a) and (b).
(d) Inhibitors Which may be used are the conventional products, e.~. hydroquinone, tert.-butylpyrocatechol, p-benzoquinone, chloranil9 nitrobenzenes, SUCh as m-dinitrobenzene, aromatic amines, such a8 thiodiphenyl~mine or 8alt8 Or N-nitroso-N-cyclohexyl-hydroxylamine8, as well a~ their mixtures. The molding materials contain preferably from 0.01 to 0.05, per cent by weight of the inhibitors, ~ased on the components (a) and (b) (e) In addition, in most cases conventional fillers, pigments, reinforcing agents and, if appropriate, inert solvents, polymeri-zation accelerators and/or other assistants usually employed in pro-cessing polyester molding materials are added to the molding m~ ~ lals employed in the process according to the invention.
~ . ._._ . ..
lOS6083 o.z. 30,881 Examples of suitable fillers are conventional finely pulverulent or granular inorganic or organic fillers, such as cement, chalk, kaolin, finely disperse silica, quartz, talcum, kieselguhr, finely particulate crosslinked organic polymers, sa~rdust, wood shavings and the likeO
Reinforcing agents which may be used are inorganic or organic fibers or sheet-like materials produced therefrom, e.g. non-wovens, mats or woven fabrics, e.g. made of glass, asbestos, cellulose and synthetic organic high polymers.
From 5 to 200, preferably from 50 to 150, per cent by weight of the fillers and reinforcing agents, based on the components (a) to (d), may be used.
Further assistants which may optionally be used at the same time are: inert solvents, e.g. ketones, esters and hydrocarbons, in amounts of from O to 10 per cent by weight based on the component (a), additives which reduce shrinkage, e.g. thermoplastic polymers, such as polyethylene, poly~tyrene, styrene copolymers, polyvinyl chloride, polyvinyl acetate and vinyl acetate copolymers, or polyacrylates or polymethacrylate~, in amounts of up to about 30 per cent by weight, based on the components (a) and (b), and also polymerization accele-rators, e.g. cobalt octoate or aromatic amines, pigments, e.g.
titanium dioxide, chromium oxide or organic pigments, mold release agents, e.g. phosphoric acid esters and metal salts of higher fatty acids, e.g. Zn stearate or Ca stearate, in amounts of from 0.05% to 5% based on the components (a) and (b), and thickening accelerators, e.g. PC13 or POC13, in amounts of about 0.02 to 0.2 per cent by weight~ based on the unsaturated polyester (a) and the monomeric vinyl compound.
Polymerization initiators which may be used for the polyester molding materials of the invention are those which are as stable as possible at room temperature but at elevated temperatures give free radicals which initiate the polymerization, e.g. peroxides, such as benzoyl peroxide, dicumyl peroxide, di-tert.-butyl peroxide, tert.-_ g _ ` 1~56083 o, z, 30,881 butyl perbenzoate or their mixtures, azo compounds, e.g. azodiiso-butyronitrile, or or~anic compounds which decompose into free radicals through scission of a C-C bond, and others.
The amount of catalyst is from 0.5 to 6 per cent by weight, advantageously from 1 to 3 per cent by weight.
The mixing of the individual components, to form the molding materials of the invention, may be carried out in conventional mixing equipment. A suitable method is to add all the additives successively, except for the alkaline earth metal oxides and the thickening accelerator, and to admix these latter materials only shortly before processing the resin batch.
The molding materials of the invention may be cured at elevated temperatures under pressure to give moldings havin~ particularly good surface glo9s. In addition to their rapid thickening it is above all the achievable viscosity levels, namely values of ~rom 109 to 101 mPa.s which are significant. These make it possible to use poly-èster, polyvinyl alcohol or polyamide release rilms which, in con-trast to polyethylene film, are very resistant to diffusion of styrene and are not swollen by styrene. After pulling off these films, the surface of the thickened molding material is tack-free and smooth even ir no fillers have been added, so that transparent molded pro-ducts can be manufactured. The polyester molding materials of the invention may be used to produce surface coatings of curable paper laminates, or to manuracture tran~parent moldings.
The materials Or the invention may al~o be used to manufacture prepregs and press-rorming materials. In these cases, their main advantage is that ripening takes place more quickly, that high vis-cosities are achieved and that at the same time they exhibit good flow during hot-pressing. As a result, moldin~ materials of reduced tackiness are obtained, which can be cured, even after extended storage, to give moldings of improved surface gloss. Similar advan-tages are found if the method of the invention is applied to the manu-facture and processing of molding materials of low shrinkage which o-L~ l .
1 0 S 6l08 3 -Z. 30,~81 additionally contain thermoplastic polymers and in general have a great tendency, after extended storage, to ~orm a deposit on the mold during hot-pressing, which has an adverse effect on the surface gloas of the molding.
Unless stated otherwise, parts and percentages in the examples are by weight.
Unsaturated polyester resins Resin A is a 65~ strength solution in styrene, stabilized with 0.01~ of hydroquinone, of an unsaturated polyester of maleic acid, o-phthalic acid and 1,2-propylene glycol in the molar ratio of 2:1:3.15. The acid number of the polyester is 50.
Resin B i8 a 65% strength solution in styrene, stabilized with 0001%
of hydroquinone, of an unsaturated polyester of maleic acid and 1,2-propylene glycol in the molar ratio of 1:1. The acid number of the polye~ter i9 18.
Resin C is a 64% strength solution in styrene, stabilized with 0.01%
of hydroquinone, of an unsaturated polyester of maleic acid, tetra-hydrophthalic acid and diethylene glycol in the molar ratio of 1:0.5:1.5. The acid number of the resin is 30.
Polyester D is a crystalline unsaturated polyester of fumaric acid, adipic a¢id and 1,4-butanediol in the molar ratio of 4:1:5. The poly-ester has an acid number of 20 and melts at 112C (Kr~mer-Sarnow-Nagel method).
Resin E is a 72% strength solution in ~tyrene, stabilized with 0.01%
of hydroquinone, o~ an unsaturated polyester Or maleic acid, 1,2-pro-pylene glycol and dipropylene glycol in the molar ratio of 1:0.78:0.33.
The polyester has an acid number of 38 and contains 0.460 equivalent of polymerizable double bonds per 100 g (double bond value).
To prepare the crystallite suspension F a mixture of 485 parts of polyester resin A, 650 parts of polyester resin B, 4~4 partæ of crystalline polyester D and 380 parts of styrene, to which 0.135 part of hydroquinone has been added, i~ heated to 110C under an inert gas, 10S60~3 o. z. 30,881 whilst stirring, and the resulting solution is then slowly cooled to room temperature~ The suspension has a viscosity of 1,000 mPas.
The crystallite suspension G was prepared analogously to sus-.
pension F from a mixture of 460 parts of crystalline polyester D, 460 parts of unsaturated polyester resin B, 358 parts of styrene and 00128 part of hydroquinone. The viscosity (at 23C) was 552 mPa.s.
EXAMPLE
A crystallite suspension which had a viscocity (at 23C) of 2.5 x 106 mPa.s wasprepared by cooling a solution, at 110C, of 2,100 parts of resin A and 1,200 parts of resin D to 50C whilst stirring and then continuing the cooling, to room temperature, with-out istirring.
To test the thickened mixture in comparison with resin A, 100 parts Or this crystallite suspension were diluted with 30 parts of styrene, which lowered the viscosity to 980 mPa.s,2 parts of magnesium oxide and 1 drop Or phosphorus oxychloride were stirred in and the mixture was stored for 24 hours at 23C.
A stiff mass of viscosity (at 25C) 2.0 x 107 mpa.s~measured on the Konsistometer from Haake, Berlin) was obtained.
Under the same ripening conditions, resin A, after addition of 30% of styrene, gave a viscosity (at 25C) of 5.9 x 105 mPa.s.
A crystallite suspension was prepared analogously to Example 1 from 2,100 parts of resin C and 1,200 parts Or resin D. 10 parts of styrene, 2 parts of magnesium oxide and 1 drop of phosphorus oxy-chloride were added to 100 parts of this viscous mixture, which was then ripened for 3 hours at 50C. Thereafter the viscosity (at 25C) was 1.7 x 109 mPa.s(measured on the Konsi~tometer from Haake, Berlin).
If resin C was thickened under exactly the same conditions after addition of 10~ of styrene, a mass having a viscosity of only
The fact that phosphorus halides are excellent thickening accelerators is disclosed, inter alia, in ~erman Patent Application P 23 11 395.3 published on May 12, 1974. By use of these halides, tack-free, very viscous molding materials can be obtained very quickly;
however, the additives disclosed do not have a favorable effect on the flow during hot-pressing, as the viscosity of the materials increases, whilst such flow is important to give optimum surrace characteristics Or the moldings.
The use Or a release film is desirable to reduce the evaporation Or styrene - conventionally used as a monomer - from the resin layer and prevent the stacked paper laminates sticking to~ether on storage.
Films of polyethylene, polyamide or polyester and polyvinyl alcohol have proved satisfactory.
From a commercial point o~ view, polyethylene films would be of particular interest, but since they swell and are permeable to styrene, an~ therefore give a wavy surface of the molding material ir thickening takes place slowly, they cannot be used for certain applications, e.~. with reactive paper laminates. The other release films mentioned above are more expensive and cannot be pulled Orr conventionally thickened unrilled molding materials without difficulty;
however, in contrast to polyethylene rilms, they do prevent major losses Or styrene and virtually do not swell in this monomer.
It is an object of the present invention to provide quick-ripening molding materials which are suitable for use with these styrene-impermeable films.
It is a rurther object of the present invention to provide molding materials based on unsaturated polyester resins which, whilst having an adequate pot li~e, thicken more quickly than conventional materials and give a very high viscosity, without an adverse effect on the rlow of the molding materials durin~ processin~
1~56083 We have found that this ob~ect is achieved by unsaturated polyester molding materials, curable in the presence of conventional polymerization initiators, and based on a mixture of (a) from 15 to 80 per cent by weight, based on the total amount of the components (a) to ~e), of at least one unsaturated poly-ester, having an acid number of from 5 to 100 and a mean molecular weight of from 50a to 10 000, (b) from 5 to 60 per cent by weight, based on the mixture of components (a) and (b), of at least one copolymerizable olefinic compound (c) from 1 to 5 per cent by weight, based on the mixture of components (a) and (b), of an alXaline earth metal oxide and/or hydroxide ~d) from O.OOS to 0.1 per cent by weight, based on the mixture of components (a) and (b), of an inhibitor selected from the group consisting of hydroquinones, quinones, nitrobenzenes, aromatic amines and salts of N-nitroso-N-cyclohexyl-hydro-xylamines and (e) assistants and additives, the improvement which comprises: using as said unsaturated poly-ester (a) from 10 to 95% by weight of at least one amorphous unsaturated polyester ~al) which is soluble in component (b) at room temperature and from 90 to 5% by weight of at least one crystalline unsaturated polyester ~a2) which has a solubility of less than 30% by weight in styrene at 23C or is insoluble in component ~b) or in the mixture of (b) and (al) at room temperature.
The present invention also relates to the use of these unsaturated polyester molding materials for covering or coating a sheetlike base of organic or inorganic fibers, and to the ~manufacture o laminates therefrom.
The molding materials of the invention are cured at room temperature or above, if appropriate in the presence of thîc ~ ng accelerators~
~ 4 lOS6083 The molding materials of the invention specifically have the advantage, over conventional unsaturated polyester resin m~lding materials, that they are tack-free and dimensionally stable at room temperature and may be cured to give transparent molded products.
The following are details relating to the components of the molding materials to be used in the process of the invention:
(a) Suitable unsaturated polyesters are the conventional polyconden-sation products of polybasic, especially dibasic, carboxylic acids and their esterifiable derivatives, which are linked by ester bonds to polyhydric, especially dihydric, alcohols and optionally additionally contain radicals of mono~asic carboxylic acids and/or radicals of monohydric alcohols and/or radicals of hydroxycarboxylic acids wherein at least some of the radicals must contain ethylenic copolymerizable groups.
The polyhydric, especially dihydric, alcohols are in general reacted in stoichiometric, or approximately stoichiometric, amounts with polybasic, especially dibasic carboxylic acids or their condensable derivatives.
(al) Suitable amorphous unsaturated polyesters are the conventional unsaturated polyesterQ, soluble in monomer (b), which are manufactured by polycondensation of a,~-unsaturated dicarboxylic acids or their anhydrides, optionally in combination with mono-carboxylic acids and/or polycarboxylic acids, and monoalcohols and/or polyalcohols, which serve as modifiers; examples of a,~-unsaturated dicarboxylic acids which may be used are fumaric acid, maleic acid, mesaconic acid, itaconic acid, methyleneglutaric acid, citraconic acid and the like or their esters or anhydrides.
Maleic acid, maleic anhydride and fumaric acid are preferred.
Examples of suitable monocarboxylic acids and/or polycarboxylic acids which act as modifiers are ethylhexanoic acid, fatty aci~ds, methacrylic acid, benzoic acid, o-phthalic acid, isophthalic acid, tetrahydrophthalic acid, tetrachlorophthalic acid, èndomethylenetetrachlorophthalic acid, hexachloroendomethylenetetra-hydrophthalic acid, succinic acid, glutaric acid, adipic acid and ~ ~ - 5 ~
.... __ . ~, pimelic acid.
Suitable alcohol components are diols, e.g. 1,2-propane-diol, 1,3-butanediol, 1,3-propanediol, ethylene glycol, diethylene glycol,-polyethylene glycol, 1,6-hexanediol, neopentylglycol, - 5a -,. ~f~, ' . , ` ~056083 o. z . 30,881 propa~e monoallylether, 1,4-butanediol, vinylglycol and dipropylene glycol, with propanediol, diethylene glycol and dipropylene glycol being preferred. Minor amounts of polyalcohols, e.g. glycerol, tri-methylolpropane and pentaerythritol, and of monoalcohols, e.g.
2-ethylhexanol or ratty alcohols, may be used at the same time.
Epoxides, e.g. propylene oxide, can also be used to manufacture the unsaturated polyesters.
The polycondensation can be carried out either in the melt, or azeotropically using an inert entraining agent, e.g. xylene, or in solution. Ir an epoxide is also used, it may be desirable to use a catalyst.
The polyesters are in general manufactured so as to give acid numbèrs of from 5 to 100 and mean molecular weights of advantageously from 1,000 to 4,000. It is also possible to use mixtures of such polyesters, and mixtures with diallyl ester prepolymers, e.g. obtained e.g. obtained from diallyl phthalate.
Amorphous unsaturated polyesters soluble in the monomer (b) are to be under~tood a~ those of which at least 60 per cent by weight di~olves in styrene at 23C.
(a2) Crystalline unsaturated polyesters, sparingly soluble or insoluble in component (b) or in the mixture o~ (b) and (al), at room temperature, which may be used accordin~ to the invention are such unsaturated polye~ters as are disclosed, e.g., in British Patent 644,287, U.S. Patent 3,510,457 and German Printed Application 1,544,673. A characteristic feature of the synthesis of these unsaturated polyesters is that symmetrical diols, e.g. 1,4-butanediol, 1,3-propanediol, 1,6-hexanediol, neopentyl glycol and hydroxyp~valic acid neopentyl glycol ester, and predominantly symmetrical dicarboxy-lic acids, e.g. fumaric acid, terephthalic acid and the like, are used.
The melting range of these crystalline unsaturated polyesters is in general from 40 to 180C, preferably from 80 to 120C, depending on their structure. Mixtures of such crystalline unsaturated polyesters, the~mol~cular r ' -O.Z. 30,881 weight of which is from 300 to 10,000, advantageously from 700 to 4,000, may also be employed. They are preferably employed as crystallite suspensions of low viscosity, which are suitably obtained by slow cooling Or the hot, agitated solution of the crystallizing polyester (a2) and the amorphous unsaturated polyester (a1) in a copolymerizable vinyl monomer. It is also possible first to cool a hot solution of the crystallizing polyester (a2) in a vinyl monomer and then to combine the resulting crystallite suspension with a solution of an amorphous polyester (a1) in the monomeric vinyl com-pound.
If the crystallite suspension obtained has too high a v~scosity, the latter can be lowered to the desired value by adding further vinyl monomer or adding a solution of an amorphous unsaturated poly-èster in the vinyl monomer at room temperature.
Crystalline unsaturated polyesters which are sparingly soluble or insoluble in the monomer or in the solution of component (a1) in the monomer are to be understood as those which have a solubility of <30 per cent by wei~ht in styrene at 23C and are at least 70%
crystalline.
According to the invention, the unsaturated polyester (a) comprises preferably from 30 to 80, per cent by weight of the soluble, amorphous unsaturated polyester (al) and preferably from 15 to 60, per cent by weight of the crystalline unsaturated polyester (a2) which is sparingly soluble or insoluble at room temperature.
The molding materials according to the invention in general con-tain from 15 to 80, preferably from 20 to 70, per cent by weight of unsaturated polyester (a) based on the total amount of the com-ponents (a) to (ej.
(b) Suitable copolymerizable olefinic monomeric compounds are the vinyl and allyl compounds conventionally used to manu~acture un-saturated polyester molding materials, e.g. styrene, substituted st renes, such as p-chlorostyrene, o~-methylstyrene or vinyltoluene, ~ ~ 7 ~
1(~560~3 0,Z. 30,881 esters of acrylic and methacrylic acid ~ith alcohols containing 1 to 18 carbon atoms, e.g. methyl methacrylate, butyl acrylate, ethyl-hexyl acrylate, hydroxypropyl acrylate and dicyclopentadienyl acrylate, acrylic and methacrylic acid amides, allyl esters, e.g.
diallyl phthalate, and vinyl ester, e.g. vinyl ethylhexanoate and vinyl pivalate, and others. In addition, minor amounts of poly-olefinic compounds, e.g. divinylbenzene or butanediol diacrylate~
may al80 be present.
Mixtures of the above olefinic monomers may aiso be used. The preferred components (b) are styrene, vinyltoluene, ~-methylstyrene and diallyl phthalate. The molding materials according to the invention in general contain preferably from 15 to 40, per cent by weight of component (b), based on the mixture of components (a) and (b).
(C) Suitable alkaline earth metal oxides are calcium oxide, calcium hydroxide and, preferably, magnesium oxide, and mixtures of the8e oxides or hydroxide5. These may also be partially replaced by zinC oxide.
In general, the molding material according to the invention contains preferably from 1.5 to 2.5, per cent by weight of component (C)~ ba8ed on the mixture of components (a) and (b).
(d) Inhibitors Which may be used are the conventional products, e.~. hydroquinone, tert.-butylpyrocatechol, p-benzoquinone, chloranil9 nitrobenzenes, SUCh as m-dinitrobenzene, aromatic amines, such a8 thiodiphenyl~mine or 8alt8 Or N-nitroso-N-cyclohexyl-hydroxylamine8, as well a~ their mixtures. The molding materials contain preferably from 0.01 to 0.05, per cent by weight of the inhibitors, ~ased on the components (a) and (b) (e) In addition, in most cases conventional fillers, pigments, reinforcing agents and, if appropriate, inert solvents, polymeri-zation accelerators and/or other assistants usually employed in pro-cessing polyester molding materials are added to the molding m~ ~ lals employed in the process according to the invention.
~ . ._._ . ..
lOS6083 o.z. 30,881 Examples of suitable fillers are conventional finely pulverulent or granular inorganic or organic fillers, such as cement, chalk, kaolin, finely disperse silica, quartz, talcum, kieselguhr, finely particulate crosslinked organic polymers, sa~rdust, wood shavings and the likeO
Reinforcing agents which may be used are inorganic or organic fibers or sheet-like materials produced therefrom, e.g. non-wovens, mats or woven fabrics, e.g. made of glass, asbestos, cellulose and synthetic organic high polymers.
From 5 to 200, preferably from 50 to 150, per cent by weight of the fillers and reinforcing agents, based on the components (a) to (d), may be used.
Further assistants which may optionally be used at the same time are: inert solvents, e.g. ketones, esters and hydrocarbons, in amounts of from O to 10 per cent by weight based on the component (a), additives which reduce shrinkage, e.g. thermoplastic polymers, such as polyethylene, poly~tyrene, styrene copolymers, polyvinyl chloride, polyvinyl acetate and vinyl acetate copolymers, or polyacrylates or polymethacrylate~, in amounts of up to about 30 per cent by weight, based on the components (a) and (b), and also polymerization accele-rators, e.g. cobalt octoate or aromatic amines, pigments, e.g.
titanium dioxide, chromium oxide or organic pigments, mold release agents, e.g. phosphoric acid esters and metal salts of higher fatty acids, e.g. Zn stearate or Ca stearate, in amounts of from 0.05% to 5% based on the components (a) and (b), and thickening accelerators, e.g. PC13 or POC13, in amounts of about 0.02 to 0.2 per cent by weight~ based on the unsaturated polyester (a) and the monomeric vinyl compound.
Polymerization initiators which may be used for the polyester molding materials of the invention are those which are as stable as possible at room temperature but at elevated temperatures give free radicals which initiate the polymerization, e.g. peroxides, such as benzoyl peroxide, dicumyl peroxide, di-tert.-butyl peroxide, tert.-_ g _ ` 1~56083 o, z, 30,881 butyl perbenzoate or their mixtures, azo compounds, e.g. azodiiso-butyronitrile, or or~anic compounds which decompose into free radicals through scission of a C-C bond, and others.
The amount of catalyst is from 0.5 to 6 per cent by weight, advantageously from 1 to 3 per cent by weight.
The mixing of the individual components, to form the molding materials of the invention, may be carried out in conventional mixing equipment. A suitable method is to add all the additives successively, except for the alkaline earth metal oxides and the thickening accelerator, and to admix these latter materials only shortly before processing the resin batch.
The molding materials of the invention may be cured at elevated temperatures under pressure to give moldings havin~ particularly good surface glo9s. In addition to their rapid thickening it is above all the achievable viscosity levels, namely values of ~rom 109 to 101 mPa.s which are significant. These make it possible to use poly-èster, polyvinyl alcohol or polyamide release rilms which, in con-trast to polyethylene film, are very resistant to diffusion of styrene and are not swollen by styrene. After pulling off these films, the surface of the thickened molding material is tack-free and smooth even ir no fillers have been added, so that transparent molded pro-ducts can be manufactured. The polyester molding materials of the invention may be used to produce surface coatings of curable paper laminates, or to manuracture tran~parent moldings.
The materials Or the invention may al~o be used to manufacture prepregs and press-rorming materials. In these cases, their main advantage is that ripening takes place more quickly, that high vis-cosities are achieved and that at the same time they exhibit good flow during hot-pressing. As a result, moldin~ materials of reduced tackiness are obtained, which can be cured, even after extended storage, to give moldings of improved surface gloss. Similar advan-tages are found if the method of the invention is applied to the manu-facture and processing of molding materials of low shrinkage which o-L~ l .
1 0 S 6l08 3 -Z. 30,~81 additionally contain thermoplastic polymers and in general have a great tendency, after extended storage, to ~orm a deposit on the mold during hot-pressing, which has an adverse effect on the surface gloas of the molding.
Unless stated otherwise, parts and percentages in the examples are by weight.
Unsaturated polyester resins Resin A is a 65~ strength solution in styrene, stabilized with 0.01~ of hydroquinone, of an unsaturated polyester of maleic acid, o-phthalic acid and 1,2-propylene glycol in the molar ratio of 2:1:3.15. The acid number of the polyester is 50.
Resin B i8 a 65% strength solution in styrene, stabilized with 0001%
of hydroquinone, of an unsaturated polyester of maleic acid and 1,2-propylene glycol in the molar ratio of 1:1. The acid number of the polye~ter i9 18.
Resin C is a 64% strength solution in styrene, stabilized with 0.01%
of hydroquinone, of an unsaturated polyester of maleic acid, tetra-hydrophthalic acid and diethylene glycol in the molar ratio of 1:0.5:1.5. The acid number of the resin is 30.
Polyester D is a crystalline unsaturated polyester of fumaric acid, adipic a¢id and 1,4-butanediol in the molar ratio of 4:1:5. The poly-ester has an acid number of 20 and melts at 112C (Kr~mer-Sarnow-Nagel method).
Resin E is a 72% strength solution in ~tyrene, stabilized with 0.01%
of hydroquinone, o~ an unsaturated polyester Or maleic acid, 1,2-pro-pylene glycol and dipropylene glycol in the molar ratio of 1:0.78:0.33.
The polyester has an acid number of 38 and contains 0.460 equivalent of polymerizable double bonds per 100 g (double bond value).
To prepare the crystallite suspension F a mixture of 485 parts of polyester resin A, 650 parts of polyester resin B, 4~4 partæ of crystalline polyester D and 380 parts of styrene, to which 0.135 part of hydroquinone has been added, i~ heated to 110C under an inert gas, 10S60~3 o. z. 30,881 whilst stirring, and the resulting solution is then slowly cooled to room temperature~ The suspension has a viscosity of 1,000 mPas.
The crystallite suspension G was prepared analogously to sus-.
pension F from a mixture of 460 parts of crystalline polyester D, 460 parts of unsaturated polyester resin B, 358 parts of styrene and 00128 part of hydroquinone. The viscosity (at 23C) was 552 mPa.s.
EXAMPLE
A crystallite suspension which had a viscocity (at 23C) of 2.5 x 106 mPa.s wasprepared by cooling a solution, at 110C, of 2,100 parts of resin A and 1,200 parts of resin D to 50C whilst stirring and then continuing the cooling, to room temperature, with-out istirring.
To test the thickened mixture in comparison with resin A, 100 parts Or this crystallite suspension were diluted with 30 parts of styrene, which lowered the viscosity to 980 mPa.s,2 parts of magnesium oxide and 1 drop Or phosphorus oxychloride were stirred in and the mixture was stored for 24 hours at 23C.
A stiff mass of viscosity (at 25C) 2.0 x 107 mpa.s~measured on the Konsistometer from Haake, Berlin) was obtained.
Under the same ripening conditions, resin A, after addition of 30% of styrene, gave a viscosity (at 25C) of 5.9 x 105 mPa.s.
A crystallite suspension was prepared analogously to Example 1 from 2,100 parts of resin C and 1,200 parts Or resin D. 10 parts of styrene, 2 parts of magnesium oxide and 1 drop of phosphorus oxy-chloride were added to 100 parts of this viscous mixture, which was then ripened for 3 hours at 50C. Thereafter the viscosity (at 25C) was 1.7 x 109 mPa.s(measured on the Konsi~tometer from Haake, Berlin).
If resin C was thickened under exactly the same conditions after addition of 10~ of styrene, a mass having a viscosity of only
3.5 x 108 mPa.s formed.
EXAM~LE 3 --.
30 ~ ~ A solution is prepared from 700 parts of resin B, 400 parts of ~A. - 12 -~ ,Trademark ` 1~56083 o. z. 30,881 crystalline polyester D and 330 parts of styrene at 1~0C under an inert gas; when cooled to room temperature whilst stirring, it gives a suspension of viscosity (at 23C) 408 mPa.s.
To test the thickening properties, a torsional rheometer (Plasto-graph type PL S3 from Brabender, Duisburg) was used. 58 g Or a mix-ture Or 100 parts o~ the above suspension and 2 parts of magnesium oxide were kneaded at 78C (kneader temperature) and 130 rpm under conditions such that no styrene was able to escape. After 20 minutes, a torque of 1.06 x 1o~2Nm was measured.
In contrast, resin B, after dilution with 30% Or styrene, did not react under the set conditions. In a further experiment, resin B
was kneaded without added styrene. Here again no thickening was observable (torque ~ 0 Nm).
In order to observe the efrect Or crystalline unsaturated poly-e~ters in unsaturated polyester resins thickened with magnesium oxide, the following experiments were carried out in a torsional rheometer (Plasti-Corder, type PL V 151, rrom Brabender, Duisburg).
70 g Or thickened unsaturated polyester resins A and ~ - see the Table - were treated in the kneader at 100C and 130 rpm, the apparatus being covered to avoid losse~ Or styrene, and the constant torque which was set up was determined. Mixtures of these thickened resins with polyester D (in the weight ratio of 7:4) were then tested under the same experimental conditions ror the torque set up. Each Of the products was taken out arter 8 minutes, and a part thereo~ was stored tightly sealed in aluminum foil for 20 hours at 23C, after which its viscosity was determined (using a Konsistometer).
TABLE
Flow o~ thickened unsaturated polye~ter resins Thickened resin. Polyester D Torque Viscosity (at 23C) arter (g) (g) (Nm) 20 hours (mPas) 70 Aaj 05.70 x 10 2 2.5 x 108 , 04.90 x 10 2 1.2 x 108 .~ ~ --13 * Trademark 1056~83 o.z. 30,881 44~5 A 25.5 1.63 x 10 2 2.1 x 109 4405 B 25.5 1.84 x 10 2 1.6 x 109 (a) Resin A was thickened with 2% of MgO and 1% of a 19% strength solution of hydrogen chloride in dimethylformamide, by keeping the mixture at 23C for 2 hours and t~en at 80C for 2 hours. ~he resin was additionally stabilized with 0.01% of p-quinone.
(b) Resin B was thickened as described under a) but using only 1.5% of magnesium oxide.
This shows that as a result of the addition of a crystalline polyester, unsaturated polyester resins thickened with alkaline earth metal oxides show better flow when warm, but at the same time show an increased viscosity at room temperature.
In order to test the effect of crystalline polyesters on the manufacture and procèssing of unsaturated polyester resin molding materials, a glass mat was impregnated with a mixture of 12.4 parts of su~pension F, 47.6 parts of resin E, 40 parts of a 33% strcngth solution in styrene of a toughened polystyrene, 60 parts of (R)Hydro-carb filler, 90 parts of a chalk filler ((R) Omya BL R 2), 3 parts of Ca stearate, 3 parts of green chromium oxide, 3 parts Or 50%
strength tert.-butyl perbenzoate and 1.5 parts of magnesium oxide, and ripened for 3 days at 23C, between films.
After removing the films, the mat was pressed in a polished steel mold for 5 minutes at 145C under 7.36 N/mm2 and the plate-shaped molding, containing about 30% of glass, was released from the mold whilst hot. The cured test specimen showed a high surface gloss.
If the crystallite suspen~ion in the above molding material recipe~ was replaced by resin E, the molding produced under otherwise identical conditions showed a markedly diminished surface gloss.
To manufacture a molding material which can be granulated and can be cured by hot-pressing to give a transparent molded product, a solution of 800 parts of polyester D, 300 parts of styrene and 310 ` 105~83 o. z. 30,881 parts Or resin C was prepared under an in~rt gas at 110C. After cooling to 50C, 100 parts of styrene, 30 parts of magnesium oxide, 3705 parts of dicumyl peroxide and 1.5 parts Or phosphorus trichloride were added and the mixture was kept at 50C for 3 hours and then cooled to room temperature. The hard mass could be pulverized and stored as a powder without tendency to block. A part of this powder was pressed for 5 minutes at 140C under a pressure of 0.98 N/mm2, giving a cured transparent molded product.
A rapid ripening experiment with unfilled unsaturated polyester resins to give tack-free films, using magnesium oxide, was carried out with suspension F. For this purpose, 100 parts of suspension F, 1.33 parts Or magnesium oxide and 1.0 part of a 10% strength solution Or phosphorus trichloride~ in dimethyl phthalate were mixed and a part Or this mixture, in the form Or a thin layer (about 1 mm) was kept at 80C between styrene-impermeable films for 10 minutes. After cooling to room temperature, it was possible to pull Orr the films without the material Or the thickened mixture adhering thereto. The viscosity (at 23C) Or the molding materia~ was 8.4 x 107 mPa.s (using a Konsistometer).
2Q A part Or the mixture was stored at 23 C and the change in vis-cosity was followed. The results in the Table show that the pot life is at least 3 hours.
Time (ho~rsj 1 2 3 4 _ Vi8co~ity (at 23C), mPas 1,3701,720 1,903 10,430 To test whether the covering rilms can be pulled Orr more easily, arter rapid ripening Or thin films Or molding material, ir in place o~ the conventional unsaturated polyester resins crystallite sus-pensions are reacted with MgO at elevated temperatures, 100 parts of resin B and, separately, 100 parts Or the suspension G prepared there-30 from, were mixed with 1.33 parts of magnesium oxide and 0.06 part of ~ - 15 -~. . ; . .. .. . . . .
1056083 o.z. 30,881 phosphorus oxychloride and the mixture was kept between cellophane and PVC films for 5 minutes at 80C and then cooled. The films could only be pulled off satisfactorily from the molding material based on suspension G, whilst the molding material based on resin B was still excessively tackyO In the latter case, thickening times of about 40 minutes at 80C were needed to permit perfect detachment of the covering films~ Similar results were obtained when the experi-ments were carried out with other films (e.g. of polyamide, polyvinyl alcohol, polyethylene or polyester) or with aluminum foil.
.
EXAM~LE 3 --.
30 ~ ~ A solution is prepared from 700 parts of resin B, 400 parts of ~A. - 12 -~ ,Trademark ` 1~56083 o. z. 30,881 crystalline polyester D and 330 parts of styrene at 1~0C under an inert gas; when cooled to room temperature whilst stirring, it gives a suspension of viscosity (at 23C) 408 mPa.s.
To test the thickening properties, a torsional rheometer (Plasto-graph type PL S3 from Brabender, Duisburg) was used. 58 g Or a mix-ture Or 100 parts o~ the above suspension and 2 parts of magnesium oxide were kneaded at 78C (kneader temperature) and 130 rpm under conditions such that no styrene was able to escape. After 20 minutes, a torque of 1.06 x 1o~2Nm was measured.
In contrast, resin B, after dilution with 30% Or styrene, did not react under the set conditions. In a further experiment, resin B
was kneaded without added styrene. Here again no thickening was observable (torque ~ 0 Nm).
In order to observe the efrect Or crystalline unsaturated poly-e~ters in unsaturated polyester resins thickened with magnesium oxide, the following experiments were carried out in a torsional rheometer (Plasti-Corder, type PL V 151, rrom Brabender, Duisburg).
70 g Or thickened unsaturated polyester resins A and ~ - see the Table - were treated in the kneader at 100C and 130 rpm, the apparatus being covered to avoid losse~ Or styrene, and the constant torque which was set up was determined. Mixtures of these thickened resins with polyester D (in the weight ratio of 7:4) were then tested under the same experimental conditions ror the torque set up. Each Of the products was taken out arter 8 minutes, and a part thereo~ was stored tightly sealed in aluminum foil for 20 hours at 23C, after which its viscosity was determined (using a Konsistometer).
TABLE
Flow o~ thickened unsaturated polye~ter resins Thickened resin. Polyester D Torque Viscosity (at 23C) arter (g) (g) (Nm) 20 hours (mPas) 70 Aaj 05.70 x 10 2 2.5 x 108 , 04.90 x 10 2 1.2 x 108 .~ ~ --13 * Trademark 1056~83 o.z. 30,881 44~5 A 25.5 1.63 x 10 2 2.1 x 109 4405 B 25.5 1.84 x 10 2 1.6 x 109 (a) Resin A was thickened with 2% of MgO and 1% of a 19% strength solution of hydrogen chloride in dimethylformamide, by keeping the mixture at 23C for 2 hours and t~en at 80C for 2 hours. ~he resin was additionally stabilized with 0.01% of p-quinone.
(b) Resin B was thickened as described under a) but using only 1.5% of magnesium oxide.
This shows that as a result of the addition of a crystalline polyester, unsaturated polyester resins thickened with alkaline earth metal oxides show better flow when warm, but at the same time show an increased viscosity at room temperature.
In order to test the effect of crystalline polyesters on the manufacture and procèssing of unsaturated polyester resin molding materials, a glass mat was impregnated with a mixture of 12.4 parts of su~pension F, 47.6 parts of resin E, 40 parts of a 33% strcngth solution in styrene of a toughened polystyrene, 60 parts of (R)Hydro-carb filler, 90 parts of a chalk filler ((R) Omya BL R 2), 3 parts of Ca stearate, 3 parts of green chromium oxide, 3 parts Or 50%
strength tert.-butyl perbenzoate and 1.5 parts of magnesium oxide, and ripened for 3 days at 23C, between films.
After removing the films, the mat was pressed in a polished steel mold for 5 minutes at 145C under 7.36 N/mm2 and the plate-shaped molding, containing about 30% of glass, was released from the mold whilst hot. The cured test specimen showed a high surface gloss.
If the crystallite suspen~ion in the above molding material recipe~ was replaced by resin E, the molding produced under otherwise identical conditions showed a markedly diminished surface gloss.
To manufacture a molding material which can be granulated and can be cured by hot-pressing to give a transparent molded product, a solution of 800 parts of polyester D, 300 parts of styrene and 310 ` 105~83 o. z. 30,881 parts Or resin C was prepared under an in~rt gas at 110C. After cooling to 50C, 100 parts of styrene, 30 parts of magnesium oxide, 3705 parts of dicumyl peroxide and 1.5 parts Or phosphorus trichloride were added and the mixture was kept at 50C for 3 hours and then cooled to room temperature. The hard mass could be pulverized and stored as a powder without tendency to block. A part of this powder was pressed for 5 minutes at 140C under a pressure of 0.98 N/mm2, giving a cured transparent molded product.
A rapid ripening experiment with unfilled unsaturated polyester resins to give tack-free films, using magnesium oxide, was carried out with suspension F. For this purpose, 100 parts of suspension F, 1.33 parts Or magnesium oxide and 1.0 part of a 10% strength solution Or phosphorus trichloride~ in dimethyl phthalate were mixed and a part Or this mixture, in the form Or a thin layer (about 1 mm) was kept at 80C between styrene-impermeable films for 10 minutes. After cooling to room temperature, it was possible to pull Orr the films without the material Or the thickened mixture adhering thereto. The viscosity (at 23C) Or the molding materia~ was 8.4 x 107 mPa.s (using a Konsistometer).
2Q A part Or the mixture was stored at 23 C and the change in vis-cosity was followed. The results in the Table show that the pot life is at least 3 hours.
Time (ho~rsj 1 2 3 4 _ Vi8co~ity (at 23C), mPas 1,3701,720 1,903 10,430 To test whether the covering rilms can be pulled Orr more easily, arter rapid ripening Or thin films Or molding material, ir in place o~ the conventional unsaturated polyester resins crystallite sus-pensions are reacted with MgO at elevated temperatures, 100 parts of resin B and, separately, 100 parts Or the suspension G prepared there-30 from, were mixed with 1.33 parts of magnesium oxide and 0.06 part of ~ - 15 -~. . ; . .. .. . . . .
1056083 o.z. 30,881 phosphorus oxychloride and the mixture was kept between cellophane and PVC films for 5 minutes at 80C and then cooled. The films could only be pulled off satisfactorily from the molding material based on suspension G, whilst the molding material based on resin B was still excessively tackyO In the latter case, thickening times of about 40 minutes at 80C were needed to permit perfect detachment of the covering films~ Similar results were obtained when the experi-ments were carried out with other films (e.g. of polyamide, polyvinyl alcohol, polyethylene or polyester) or with aluminum foil.
.
Claims (4)
1. In unsaturated polyester molding materials, curable in the presence of conventional polymerization initiators and based on a mixture of (a) from 15 to 80 per cent by weight, based on the total amount of the components (a) to (e), of at least one unsaturated poly-ester, having an acid number of from 5 to 100 and a mean molecular weight of from 500 to 10 000, (b) from 5 to 60 per cent by weight, based on the mixture of components (a) and (b), of at least one copolymerizable olefinic compound (c) from 1 to 5 per cent by weight, based on the mixture of components (a) and (b), of an alkaline earth metal oxide and/or hydroxide (d) from 0.005 to 0.1 per cent by weight, based on the mixture of components (a) and (b), of an inhibitor selected from the group consisting of hydroquinones, quinones, nitrobenzenes, aromatic amines and salts of N-nitroso-N-cyclohexyl-hydroxy-lamines and (e) assistants and additives, the improvement which comprises: using as said unsaturated polyester (a) from 10 to 95% by weight of at least one amorphous unsaturated polyester (a1) which is soluble in component (b) at room temperature and from 90 to 5% by weight of at least one crystalline unsaturated polyester (a2) which has a solubility of less than 30% by weight in styrene at 23°C or is insoluble in component (b) or in the mixture of (b) and (a1) at room temperature.
2. In a process for the manufacture of curable unsaturated polyester molding materials by mixing (a) from 15 to 80 per cent by weight, based on the total amount of the components (a) to (e), of at least one unsaturated polyester, having an acid number of from 5 to 100 and a mean molecular weight of from 500 to 10 000, (b) from 5 to 60 per cent by weight, based on the mixture of components (a) and (b), of at least one copolymerizable olefinic compound (c) from 1 to 5 per cent by weight, based on the mixture of components (a) and (b), of an alkaline earth metal oxide and/or hydroxide (d) from 0.005 to 0.1 per cent by weight, based on the mixture of components (a) and (b), of an inhibitor selected from the group consisting of hydroguinones, quinines, nitrobenzenes, aromatic amines and salts of N-nitroso-N-cyclohexyl-hydroxy-lamines and (e) assistants and additives, the improvement which comprises: using as said unsaturated polyester (a) from 10 to 95% by weight of at least one amorphous unsaturated polyester (a1) which is soluble in component (b) at room temperature and from 90 to 5% by weight of at least one crystalline unsaturated polyester (a2) which has a solubility of less than 30% by weight in styrene at 23°C or is insoluble in component (b) or in the mixture of (b) and (a1) at room temperature.
3. A process for covering or coating a sheet-like base material of organic or inorganic fibers with unsaturated polyester molding materials as claimed in claim 1.
4. A process for the manufacture of moldings, wherein unsaturated polyester molding materials according to claim 1 are hot-pressed.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19742447852 DE2447852A1 (en) | 1974-10-08 | 1974-10-08 | MOLDING COMPOUNDS BASED ON UNSATURATED POLYESTER RESINS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1056083A true CA1056083A (en) | 1979-06-05 |
Family
ID=5927773
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA236,945A Expired CA1056083A (en) | 1974-10-08 | 1975-10-01 | Quick-ripening unsaturated-polyester molding materials |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA1056083A (en) |
| DE (1) | DE2447852A1 (en) |
| FR (1) | FR2287479A1 (en) |
| GB (1) | GB1519519A (en) |
Families Citing this family (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6025259B2 (en) * | 1976-06-03 | 1985-06-17 | ヤマハ株式会社 | Manufacturing method of patterned molded body |
| US4189452A (en) * | 1977-12-30 | 1980-02-19 | Owens-Corning Fiberglas Corporation | Polyester resin composition |
| DK424279A (en) * | 1978-10-13 | 1980-04-14 | Metzeler Schaum Gmbh | PROCEDURE FOR THE MANUFACTURING OF FORMULAS |
| IT1114722B (en) * | 1979-02-15 | 1986-01-27 | Pro Sac Spa | POLYESTER BASED POLYMER COMPOSITION AND ITS USE FOR THE PRODUCTION OF FLEXIBLE TRANSPARENT LAMINATES WITH CHARGES OF WHOLE AND / OR FIBROUS MATERIALS |
| US4260538A (en) * | 1979-09-27 | 1981-04-07 | The Budd Company | Matured moldable thermosetting dual polyester resin system |
| DE3279104D1 (en) * | 1981-12-03 | 1988-11-17 | Scott Bader Co | Thickened moulding compositions |
| NL8701932A (en) * | 1987-08-18 | 1989-03-16 | Dsm Resins Bv | THERMO-HARDBAR COMPOSITION. |
| DE9404313U1 (en) * | 1994-03-09 | 1994-07-14 | Mehnert & Veeck Gmbh & Co Kg | Adhesive for gluing metallic surfaces in particular |
| DE4415102A1 (en) * | 1994-04-29 | 1995-11-02 | Basf Ag | Headlamp reflectors that can be directly metallized |
| CN110938290A (en) * | 2019-11-29 | 2020-03-31 | 浙江光华科技股份有限公司 | Modified bio-based high-corrosion-resistance super-wear-resistance polyester resin and preparation method thereof |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB815084A (en) * | 1954-12-29 | 1959-06-17 | British Industrial Plastics | Polyester resin compositions |
-
1974
- 1974-10-08 DE DE19742447852 patent/DE2447852A1/en active Pending
-
1975
- 1975-10-01 CA CA236,945A patent/CA1056083A/en not_active Expired
- 1975-10-06 FR FR7530517A patent/FR2287479A1/en active Granted
- 1975-10-07 GB GB4096775A patent/GB1519519A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| GB1519519A (en) | 1978-07-26 |
| FR2287479A1 (en) | 1976-05-07 |
| DE2447852A1 (en) | 1976-04-15 |
| FR2287479B1 (en) | 1978-10-13 |
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