NL7908221A - PRODUCTS FOR THE MANUFACTURE OF FOAMS OF POLYVINYL CHLORIDE RESIN. - Google Patents

Description

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Products for the production of polyvinyl chloride resin foams.

The invention relates to a product suitable for the production of foams of a polyvinyl chloride-based resin.

In the prior art, foams 5 of polyvinyl chloride based resins (hereinafter abbreviated as PVC resins) are manufactured according to several different principles. For example (I), the resin is mixed or impregnated with a decomposable foaming agent, which is a compound which can decompose at elevated temperature under gas evolution, and the resin mixture 10 is mechanically processed under heating using the techniques of extrusion molding, injection molding or other conventional molding procedures, in which the resin is expanded into a foam by the gas formed in the decomposition of the foaming agent, (2) a so-called plastisol of a pasty consistency is first prepared by mixing the resin with a plasticizer and the plastisol is processed into a foam with air entrainment using a suitable mechanical agent or otherwise the plastisol is further mixed with a decomposable foaming agent and the mixture subjected to heating, the foaming agent being decomposed to form a gas, simultaneously with the gelation of the plastisol, (3) becomes a resin mixture containing a decomposable s foaming agent, first processed into molded articles, such as plates, slabs, rods, tubes and the like, by rolling or other suitable mechanical means at a temperature lower than the decomposition temperature of the foaming agent, and then the molded article is heated to expand into a foam by effecting the decomposition of the foaming agent or (4) a metal form is filled with a resin mixture containing a decomposed foaming agent, optionally with the addition of a volatilizable foaming agent, an organic solvent, with which the resin is swellable, and a softening agent, and the resin mixture is heated under pressure in the metal mold to melt and gel, and then cooled to room temperature while still under pressure in the metal mold, forming a molded article is obtained, which is then heated again at a temperature higher than the softening temperature of the resin in order to effecting an expansion of the resin mixture into a foam by means of the gas formed by the decomposition or volatilization of the foaming agents.

As can be seen from the above description, the gas which causes the expansion of the resin mixture and is entrapped in the foams of the PVC resin is usually either the atmospheric air entrained by a mechanical agent, or a gas which is a decomposition product of the decomposable foaming agent. However, the mechanical entrapment of the atmospheric air is unsatisfactory because foams with a fine and uniform cell structure and high expansion can thus hardly be obtained even with the use of a very complicated mixing device, while the use of a decomposable foaming agent it is undesirable if foams of a high whiteness PVC resin are desirable because most of the decomposable foaming agents used in practice are azo compounds which resist colored decomposition products which necessarily lead to a yellowish or brownish discoloration of the resin foams produced. Furthermore, the cellular structure of the resin foams obtained with a decomposable foaming agent is not always satisfactory as far as their fineness and uniformity are concerned, especially when high expansion resin foams are desirable.

Except for the above drawbacks, the methods (1) - (3) described above are not suitable for the preparation of rigid or semi-rigid foams with a high degree of expansion, that is, these methods are limited to the manufacture of soft or flexible resin foams, and method (4) is disadvantageous from 79 0 8 2 2 f.

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9 c t% 3 from the viewpoint of efficiency and production costs, because the process has to be carried out batch-wise (discontinuously) and the time required for the batch-free preparation of the foam is necessarily considerable due to the complexity of the process.

Another source of the gas in the resin foams is a volatilizable foaming agent, which is a relatively low boiling point compound, which is relatively easily converted to a gas when the resin mixture containing this compound is heated so that when the heating temperature above the resin softening point, resin foams are obtained. This group of foaming agents is desirable because of the absence of colored decomposition products which lead to the discoloration of the resin foams because the formation of the gas is accomplished not by decomposition but merely by evaporation of the foaming agent. -

The use of a volatilizable foaming agent has been successful in the manufacture of various types of plastic foams, such as foams of polystyrene resins, but no successful process has so far been developed for the preparation of foams of PVC resins, although the reason for the difficulty has not been fully investigated so far.

The object of the invention is to provide a new product suitable for the manufacture of foams of a PVC resin containing a volatilizable type foaming agent, with which resin foams with a high degree of expansion and a fine and uniform cell structure can be easily obtained without notable or discernible discoloration.

The foam-expandable resin product of the invention comprises a PVC resin having an average degree of polymerization of no more than 0.20 ml per gram of the resin and a volatilizable foaming agent, which has a boiling point hydrocarbon or halohydrocarbon compound not higher than 90 ° C and impregnated into the above PVC resin.

The resin product described above can be expanded into high expansion foams with a satisfactory and fine uniform cell structure in most cases.

79 0 8 2 2 T

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However, the cell structure is not always as fine and uniform when the expansion ratio is extremely high to obtain resin foams with a bulk density of, for example, 0.10 g / cm or less.

Further investigations were carried out to obtain a resin product which can be expanded into extremely high expansion resin foams, yet having a very fine and uniform cell structure; thus an improvement was found according to which the above-described product of the PVC-10 resin impregnated with a volatilizable foaming agent is further mixed with 0.5-30 parts by weight of a foam-conditioning resin per 100 parts by weight of the PVC- resin product impregnated with the foaming agent. The foam-conditioning resin proposed herein is either an acrylic resin or a styrene-based resin, in particular without a reduced viscosity of at least 3.0 dl / g. The effect of the aforementioned foam-conditioning resin can be better demonstrated when small amounts of a nucleating agent are included in the resin product, which is a finely divided inorganic powdery material or a combination of solid reaction components, which can form carbon dioxide gas upon reaction in the resin product.

The main component in the product of the invention is a PVC resin, which is a homopolymer or a copolymer consisting essentially of vinyl chloride. When the PVC resin 25 is a copolymer, the content of the monomer or monomers copolymerized with vinyl chloride is preferably no more than 40% by weight, i.e. at least 60% by weight of the resin component is vinyl chloride, because the Resin foams thus obtained exhibit excellent flame retardancy, high mechanical strengths and other desirable properties inherent in vinyl chloride resins.

The ethylenically unsaturated monomers which are copolymerizable with vinyl chloride are well known in the art and examples thereof are vinyl esters such as vinyl acetate and vinyl propionate, vinylidene halides such as vinylidene chloride and vinylidene fluoride, vinyl halides other than vinyl 7908221 Λ · >.

Chloride, such as vinyl fluoride, acrylic acid and. esters thereof, such as ethyl acrylate, methacrylic acid and esters thereof, such as methyl methacrylate, acrylonitrile, methacrylonitrile, maleic acid and esters and anhydrides thereof, fumaric acid and esters thereof, and olefins such as ethylene and propylene.

Of the above comonomers, vinyl acetate is particularly advantageous because a copolymer of vinyl chloride and vinyl acetate is not only amenable to impregnation with a foaming agent, but also has a significantly reduced melt viscosity, ensuring an easy foaming process, resulting in the formation of resin foams with a further improved fine and uniform cell structure. In order to be able to expect such an advantageous effect when using the copolymer, the content of vinyl acetate in the copolymeric resin is desirably at least 3 wt%, the upper limit being, of course, 40 wt%, as stated above, based on of the desirable flame retardancy and mechanical properties of the resulting resin foams.

The parameters essential for the PVC resins used in the resin product of the invention are the average degree of polymerization and the pore volume. The average degree of polymerization, which can be easily determined by measuring the solution viscosity of the resin, is preferably no greater than 2000, because a PVC hats with an average degree of polymerization above 2000 has an extremely high melt viscosity and shows poor gelation so that high expansion resin foams can hardly be obtained even with a large amount of the foaming agent impregnated into the resin. On the other hand, the lower limit of the average degree of polymerization is determined from the mechanical properties of the resin foams prepared with the resin. For example, a PVC resin with an average degree of polymerization of less than 300 can give only fragile and mechanically inferior resin foams.

Another important parameter, required in the PVC resin in the product of the invention, is the pore volume, which desirably does not exceed 0.20 ml / g or more when

790822T

Jr 6 * * approve 0.10 ml / g of the resin, which value of the pore volume is extremely small compared to ordinary PVC resins with a pore volume of about 0.25 ml / g or more when the resin is a vinyl chloride homopolymer The pore volume is a value determined by a mercury compression porosimeter, 2 where the mercury pressure is increased from 1 to 100 kg / cm so that the mercury is pressed into the pores of the pore diameter resin particles of about 30 µm or less-

The above-mentioned pore volume limitation is very essential because a larger pore volume PVC resin exhibits poor retention of the foaming agent and allows the foaming agent to spread not only when stored; resin product impregnated with the foaming agent, but also in the forming process of the resin product 35. into a shaped object of the resin foams, so that foamed bodies (objects) with a high expansion cannot or hardly be obtained.

The PVC resins, which can meet the above requirements, are obtained by suspension polymerization of vinyl chloride monomer or a monomer mixture consisting essentially of vinyl chloride monomer, in an aqueous medium containing a suspending agent, in the presence of a free radical -cale polymerization initiator which is soluble in the monomer phase.

The volatilizable foaming agent to be impregnated into the PVC resin described above is, as mentioned above, a hydrocarbon or a halohydrocarbon compound having a boiling point of no higher than 90 ° C or preferably no higher than 70 ° C because, when a foaming agent having a boiling point above 90 ° C is used, the resin foams upon expansion show considerable shrinkage, so that the resulting foamed article has a cellular structure which is not satisfactory in fineness and uniformity.

The hydrocarbon or halo-hydrocarbon-'35 compounds, which may suitably be used as foaming agents in the product of the invention, are, for example, propane, 7908221% 7 butane, isobutane, pentane, neopentane, n-hexane, isohexane, n-heptane, methyl chloride , methylene chloride, chloroform, carbon tetrachloride, ethylidene chloride, ethyl fluoride, tri-chloro ethylene, 1,2-dichloroethane, trichlorofluoromethane, dichloro-5 difluoromethane, chlorotrifluoromethane, bromotrifluoromethane, tetrafluoromethane, dichlorofluoromethane, chlorodifluoromethane, trifluoromethane, triehloortrifluorethaan, dichloro tetra fluoro ethane, dibromotetrafluoroethane, chloropentafluoroethane, hexafluoroethane, 1-chloro-1,1-difluoroethane and the like. It will be appreciated that these volatilizable foaming agents can be used in combinations of two or more thereof.

The degree of impregnation of the PVC resin with the above-mentioned volatilizable foaming agent depends on the desired degree of expansion in the resin foams. It will be appreciated that the amount of the impregnation must be increased when a foamed article having a high expansion ratio is desirable and when a foamed article having a low expansion is desirable, a small amount of only 3% by weight or less of the impregnation with the foaming agent may sometimes be sufficient. However, the amount of the foaming agent is in the range of 1-30 wt% or higher in most cases where foamed articles with an appropriate expansion are to be obtained.

The impregnation of the PVC resin with the volatilizable foaming agent as mentioned above is in principle carried out by contacting these components. More specifically, the powdered PVC resin can be mixed only with the blowing agent so that the blowing agent is adsorbed into the resin particles. When the foaming agent is gaseous at room temperature under atmospheric pressure, a suitable method of impregnation is to add the PVC resin, water and dispersant to a pressure vessel, eg, an autoclave, equipped with a stirrer, to form a suspension of the resin powder in the aqueous medium and then adding the foaming agent to the suspension under pressure increase, followed by stirring the mixture under temperature increase to 30-90 ° C for 3-20 hours. After an absorption equilibrium is established within the vessel and the mixture is cooled to room temperature, the resin is removed from the vessel with the adsorbed foaming agent, dewatered using a suitable method, e.g. centrifugal separation, and dried in an air stream at a relatively low temperature of, for example, 50 ° C or less, to obtain the desired PVC resin impregnated with the foaming agent.

The resin product thus prepared, impregnated with the volatilizable foaming agent, can be processed as such into molded resin foam articles using a known technique, such as injection molding and extrusion molding as well as compression molding in a metal mold, in which the gelation of the resin and the expansion of the gelled resin by the gas formed by the evaporation of the foaming agent take place simultaneously. Optionally, the resin product for its processing can be mixed with certain kinds of additives commonly used in the formation of PVC resins, such as plasticizers, flame retardants, antioxidants, anti-static agents and the like, at a relatively low temperature to prevent premature evaporation of the foaming agent.

As mentioned above, one of the difficulties in manufacturing a foamed article from PVC resins is to ensure the fineness and uniformity of the cellular structure of the resin foams, especially when the expansion ratio of the foam is extremely high or when the said foams have a bulk density of, for example, 0.10 g / cm or less. Of course, depending on the manufacturing conditions, the foams may have a bulk density of about 0.30 g / cm. Investigations were conducted to find a cell structure conditioning agent by adding a foam conditioning agent to the resin product, and found that the addition of certain types of thermoplastic resins are particularly effective for this purpose.

The foam conditioning resins of the invention include acrylic resins and styrene-based resins, and these resins are particularly effective when they have a reduced 7908221 9 κ viscosity of at least 3.0 dl / g as measured in a chloroform solution of 0.1 g / Have 100 ml concentration at 25 ° C. These foam conditioning resins are mixed with the PVC resin impregnated with the volatilizable foaming agent in an amount of 0.5-30 parts by weight per 100 parts by weight of the PVC resin impregnated with the foaming agent, before the resin product is formed into molded resin foam articles.

The acrylic resin suitable as a foam-conditioning resin is either a polymethyl methacrylate or a copolymer resin consisting essentially of methyl methacrylate and one or more acrylic esters such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate and the like. The acrylic resin may also contain comonomers other than the above-mentioned, such as styrene, acrylonitrile, vinyl esters and other esters of methacrylic acid other than methyl methacrylate, such as ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate and the like, provided their contents are limited. In any case, the content of methyl methacrylate in the acrylic resin is preferably in the range of 60-95% by weight.

It is desirable that the acrylic resin as the foam conditioning resin has a reduced viscosity of at least 3.0 dl / g or preferably at least 5.0 dl / g as measured in a chloroform solution at a concentration of 0.1 g / 100 ml at 25 ° C as stated above.

It is recommended to use an acrylic resin with a higher reduced viscosity or, in other words, with a higher average degree of polymerization when the average degree of polymerization of the PVC resin strongly approaches the upper limit of 2000. Furthermore, it is preferable to use an acrylic resin prepared by emulsion polymerization of the acyl monomers, because further improvements are obtained when using such a resin in terms of the ease of feeding the molding machines with a reduced risk of clogging of the inlet of the resin product, fed to the machine, in addition to the acceleration of the uniform gelation of the resin product and greater expandability of the 7908221

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gelled and melted resin product.

The amount of the acrylic resin as a foaming conditioner to be admixed is 0.5-30 parts by weight or preferably 3-20 parts by weight per 100 parts by weight of the PVC resin impregnated with the foaming agent, because larger amounts of the acrylic resin than the above amounts do not give any further improvement and instead an undesirable influence is exerted on the properties inherent in PVC resins, such as the flame retardancy.

Styrene based resins belong to another group of the foam conditioning resins. The styrene-based resin may be a styrene homopolymer, but the styrene-based resin is preferably a copolymer consisting essentially of styrene with a small amount of acrylonitrile as the monomer. The copolymer may, of course, optionally contain one or more other comonomers which are copolymerizable with styrene and acrylonitrile.

In any case, the styrene-based resin has a reduced viscosity of at least 3.0 dl / g as measured in a chloroform solution of 0.10 g / 100 ml concentration at 25 ° C. It is recommended that the styrene-based resin have the highest possible reduced viscosity when the vinyl chloride-based resin has a large average degree of polymerization approaching the upper limit of about 2000.

The above-mentioned comonomers, which are copolymerizable with styrene and acrylonitrile, are, for example, esters of acrylic acid, such as methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate and the like, esters of methacrylic acid, such as methyl methacrylate, n-methyl methacrylate methacrylate, 2-ethylhexyl methacrylate and the like, maleic acid and fumaric acid and esters thereof, and maleic anhydride.

The above-described styrene-based resins are obtained by a known polymerization method, but the resin is preferably prepared by emulsion polymerization in an aqueous medium.

The amount of the styrene-based resin to be used as a foaming conditioner can be reduced by 79-0 8 2 2! 11 * are the same as for the acrylic resins, i.e. range from 0.5-30 parts or preferably 3-20 parts per 100 parts by weight of the PVC resin impregnated with the volatilizable foaming agent .

The mechanism by which the significant improvement in the cellular structure of the resin foams is obtained by adding the foam-conditioning resin is believed to be that the gelation of the PVC resin is accelerated by the foam-conditioning resin and the melt viscosity of the resin. PVC resin in the molding stage is appropriately controlled or enlarged to increase the expandability of the foams and to reinforce the cell walls of the foams, thereby providing a higher resistance to contamination or collapse of the foams, while additionally shrinking the foaming once-formed at elevated temperature is prevented with improved gas retention formed by the evaporation of the foaming agent.

It has further been found that the above-described foam conditioning effect, obtained by adding a foam conditioner resin, is further improved when some kinds of nucleating agents are present in combination with the foam conditioner resin. A group of nucleating agents suitable for use in the invention are inorganic fine powder materials such as calcium carbonate, talc, barium sulfate, fumed silica, titanium dioxide, clay, alumina, bentonite, diatomaceous earth and the like. average particle size of 30 µm or less, or preferably 10 µm or less, because coarser particles of these inorganic powders adversely affect the fluidity (flowability) of the molten resin 30 at the molding step, so that the surface condition of the foamed articles obtained by admixing such a coarser powder are sometimes unsatisfactory in gloss, while streaking may also occur and the cell structure does not have satisfactory uniformity.

Another group of nucleating agents is formed by a combination in approximately equivalent amounts of an acid, such as boric and organic acids, for example citric, tartaric and oxalic, and a carbonate or hydrogen carbonate of sodium , potassium or ammonium, such as sodium carbonate, sodium hydrogen carbonate, potassium carbonate, ammonium hydrogen carbonate and the like.

The amount of the nucleating agent to be added in combination with the foaming conditioning resin is in the range of 0.01-20 parts by weight per 100 parts by weight of the PVG resin impregnated with the foaming agent . When the amount of the nucleating agent is greater than 20 parts by weight, the expansion ratio of the foamed resin is reduced and the resulting foamed article has inferior properties, including less smooth surfaces.

The resin product of the invention may optionally be mixed with a known decomposable foaming agent provided that the amount thereof is limited to, for example, 5 parts by weight or less per 100 parts by weight of the PVC resin impregnated with the volatilizable foaming agent. The decomposable foaming agent which can be suitably used consists, for example, of an azo-20 compound, such as azodicarbonamide, azobisisobutyronitrile, diazoamine benzene, diethylazodicarboxylate, diisopropylazodicarboxylate and the like, nitroso compounds such as N.N'-dinitrosopenta-methylene tetramethylene tetramethyl -N.N'-dinitrosoterephthalamide and the like and sulfonylhydrazine compounds, such as benzenesulfonyl-hydrazide, toluenesulfonylhydrazide, 4.41-oxy-bis (benzenesulfonyl-hydrazide), 3,3-di (sulfonhydrazide-phenyl) sulfone, toluene-disulfonyl-hydrazone, (benzenesulfonylhydrazide), toluene sulfonyl azide, toluene sulfonyl semicarbazide, 4,4'-oxy-bis (benzenesulfonyl hydrazide) and the like as well as sodium hydrogen carbonate.

The use of these decomposable foams is desirable to further improve the fineness and uniformity of the cellular structure of the resin foams and to reduce shrinkage of the foamed article, so that the shape of the foamed article is better maintained, although a too large an amount of the decomposable foaming agent is undesirable due to the discoloration of the foamed article due to its colored decomposition products and the rougher surface condition of the foamed article without additional benefits. It is also advisable to add a decomposition promoter known in the art, such as certain types of zinc compounds, copper compounds and the like, to accelerate the decomposition of the decomposable foaming agent and the gas evolution at a temperature lower than the temperature in the formation of the resin product.

The expandable resin product described above with admixture of the foam-conditioning resin is very advantageous in the production of molded articles of the PVC resin foams, because the product can give resin foams with a high expansion and with a fine and uniform cell structure regardless of the stiffness of the desired foamed products, which ranges from soft and flexible to hard and rigid, using any conventional continuous manufacturing procedures, including extrusion molding, injection molding, compression molding and the like, the cost not being particular need to be taken into consideration.

The invention is further illustrated but not limited by the examples below. In the examples, the parts are parts by weight. The methods for determining the amount of the impregnated volatilizable foaming agent in the PVC resin and the pore volume of the resin are described below. The amount of impregnation of the volatile foaming agent: The PVC resin, impregnated with the volatilizable foaming agent, is heated in an air oven at 130 ° C for 2 hours and the amount of impregnation is calculated from the equation (Wj - X CO »where Wj and Wj are the weights before and after heating, respectively.

Pore volume of the PVC resin: The pore volume is calculated with a mercury compression porosimeter of

Model 70H, manufactured by Carl Erba Co., where the pressure of the mercury is increased from 1 to 100 kg / cm, and is expressed in 35 ml per gram of the resin.

7908221

Example I

(Tests 1-13).

14

1000 g of a vinyl chloride-homo-5 polymer or a copolymer resin consisting of vinyl chloride and vinyl acetate, as indicated in Table A below, in which P and Vp represent the average polymerization, were charged into a 5 liter autoclave equipped with a stirrer. grade and pore volume of the resin, 2000 g of purified water, and 150 g of trichlorofluoromethane and further 200 g of butane were fed under pressure, followed by a temperature increase with stirring to 70 ° C and a continued stirring at the same temperature for 8 hours to impregnate the resin with trichlorofluoromethane and butane as volatilizable foaming agents.

After cooling to room temperature and removing the excess foaming agents from the autoclave, the resin so impregnated was removed from the autoclave, dewatered and dried in an air stream at 40-50 ° C for about 8 hours.

The amount of impregnation with the foaming agents in the resin was determined immediately after preparation and after storage at 20 ° C for 1 week to obtain the results shown in Table A.

The resin obtained in the manner described above, impregnated with the foaming agents, in an amount of 100 parts was mixed with 2 parts of a tin-containing stabilizing agent and 1 part of calcium stearate and the resin mixture was processed into a foamed article in the mold of a cylindrical rod by extrusion molding in an extruder, which was operated under the conditions indicated below.

The bulk density of the foamed article obtained from each of the tests is shown in the table.

The operating conditions of the extruder are listed below. .

Diameter of the screw 20 mm 35 Length of the screw 400 mm

Compression ratio of the screw 3.0 790822! 15

Die 5 mm diameter of the opening and 70 mm land length

Screens one with 80 mesh opening and one with 100 mesh opening

5 Temperature of the cylinder Cj = 60 - 120 ° C

C2 = 100-160 ° C

C3 = 120-180OC

Temperature of the mold about 130 C.

Rotation speed 50 r.p.m.

The foamed article obtained in Test 9 was very fragile. Although the foamed article obtained in Test 11 had a high expansion ratio, it was inferior in flame retardancy.

15 7908221 16 co o o to lh - O co σ co co O Λ Λ Λ Λ - Ο - Ο - (Ν co om * - «ο cm ιο co cm P ** Λ ft ft ft Ο CM Ο -.

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Cd ο co <f to Η ο- ο · »Λ« σ co ο ο co cm ο σ ο <τ ο

r- ~ CM Ο ft. ft VO

ΙΟ Ο - Ο Ο Ο ”" Ο CM Ο. Ο Ο - ο - - -cf to <f Ο * ft Ό ft Ο σ Ο Ο I- "- - ο σν co ι— to ο ο Ρ» ιο Ο Ο Ο Ο ff *) IS ft A »» ο οο r »ο _______ 1 rl 6vS rd <u cd - ω o ui ^ οο ι ω oc

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pi cd-«3 -i-f · ι-> 4-1 O

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(3 | | Λ CU · Η ÖO

0000 grHB-ξ C50S ^ in as · η ui · μ i 0) | C0 i-l-HDTJ & MCJPi o um ft i4 μ i ό a own n t> cd gaau-HU) uaa

Pm PM M3 H d g a MMS

7808221 17

Example II

(Tests 14 - 26).

1000 g of a copolymer resin, consisting of 88 wt.% Vinyl chloride and 12 wt.% Vinyl acetate, with a pore volume Vp of 0.010 ml / g and an average degree of polymerization P of approximately 650, 2000 were charged into the same autoclave as used in Example 1. g of purified water and 1.0 g of a partially saponified polyvinyl alcohol and further, one or two types of volatilizable foaming agents as indicated in Table 10 below were autoclaved in the amounts indicated in the table, if necessary, under compression, for 8 hours Stirred at 70 ° C to impregnate the resin with the foaming agents.

The abbreviations for the volatilizable foaming agents used in this example are indicated below and these abbreviations will also be used in the other examples.

PR * propane PE = pentane 20 HE - n-hexane TCFM = trichlorofluoromethane MC = methyl chloride BU * butane MEC - methylene chloride 25 DCTFE = dichlorotetrafluoroethane DCDFM = dichlorodifluoromethane DCFM = dichlorofluoromethane TCDFE = ISOFluoromethane TCDFE =

The amount of impregnation with the foaming agents and the bulk density of the foamed article in the form of a cylindrical rod, manufactured in the same manner as described in Example I, are shown in Table B. The foamed articles of Runs 24-26 showed a strong shrinkage after formation.

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ο ο σι co ο to o · »* · CM H IN r- 'o ____________

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_._ E ± P3 ____ / -s O IT) HO *> P '· <ί ÜO -

CM H cm - O

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OpO + UO «t'- cm pq owo <ro cs S ^ ^ Λ '- --- o er, pomo - pq O ·> - CO O« w - Ο pq co oo' pq o '- - go + po «Co, -H CM CM O - '(U w s-' CM« S ___.____ H a / -> o ο * pt, ο * σ, - ο ο σ> ο El CO - '

w O

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1-1 pc O «CM

CO O Λ

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CU 3 p & 0 3 15 hi O Ij g o, ö ft i i η m oücoo- ^ ·

U O g -rl O <U ÖO W M O O M

p co η μ cd ^ co 13 ω 7908221.

Example III

(Tests 27 - 33).

19

Into an autoclave with a capacity of 100 liters, made of stainless steel and equipped with a stirrer, were placed 30 kg of the same copolymer resin of vinyl chloride and vinyl acetate as used in example II, 50 kg of purified water and 15 g of a partially saponified polyvinyl alcohol and further, a mixed foaming agent consisting of butane and trichlorofluoromethane in a ratio of 2: 1 was autoclaved under pressure in an amount as indicated in Table C below, followed by stirring for 8 hours at a temperature as indicated in the table to impregnate the resin with the foaming agent. Dewatering and drying of the resin impregnated with the foaming agent was carried out in the same manner as described in Example 1. The amount of impregnation with the foaming agent is shown in Table C.

Resin mixtures were prepared from 100 parts of the obtained resin described above, impregnated with the foaming agent, 2 parts of a tin-containing stabilizer and 20 1 parts of calcium stearate and the resin mixture was processed into a foamed article in the form of a slice by extrusion molding using an extruder, which was operated under the conditions indicated below.

The foamed articles thus obtained were subjected to a determination of the bulk density, the thermal conductivity as measured at 20 ° C according to the method described in JIS A 1413, and the compression strength as measured at 20 ° C according to the method described in ASTM D 1621 to obtain the results shown in Table C.

30 The operating conditions of the extruder are shown below.

Diameter of the screw 65 mm

Length of the screw 1300 mm

Compression ratio of the screw 2.0 35 Die 100 mm width and 8 mm height 7908221 20

Fencing one with 80 mesh opening and

one with 100 mesh opening Cylinder temperature Cj = 80 ° C

C2 = 120 ° C

C3 = 150 ° C

Temperature of the mold 120 ° C

Rotation speed 30 r.p.m.

10 7908221 21 oo m o o s 5 s ° * 2 2 § - o \ VO co oo o o * es vo m o »* ^ CO CO" —1 OD o o 1Λ - vO «A * - J5 * T,

CO CO O O

er> “O 'o o * in CO co o - o CO o O“ co - r ». "" Ό

o o

«Os * n os oo o cm in °« ^ - ® ° vo O o o

T-C

_____________ -8 Ê-1 o

CO vO O CS oo CO <N

es f »~ O o" 00 "” o o - co CO sr o r- CO O O - o “CS Γ ·» ·> “os LD O o co • | / -s

rr) + J | g 03 3 CM

rj 4J O t — 1 4J * rl O O i— * CJ M U

Ö ^ 4J u -π g g <u ω g rt o g. I u g o <u o & ^ μ r-ι g n ö q · gajqcp

S O g 4-1 01 ÖO af al -r4 0) 0), Ü G O γΙ 4-1 rW

So w cn oo'- 'ts öo' O> öo ^ rG u os os'- '1—1 001 — I "

U <U M G <D

• rl fl G · Η Ό • ai * ö 3 M> d O, G -H 4J 0) -rj G _ p <

g H Ë ^, cd C 0Λ <u I 'g M

aigöOM oo g s-s i p. a> g <um αι · ΗΛί a) ai · η · G o, öo · η 5 ai> G '^ & i-iGS a »G _ 3 ho ai -G gg ,, g ai öo, g G, fi o μ ou ai guöo -hugoo HB ® E-ï {—1 03 WW> M> 79 0 8 2 2 f

Example IV

(Tests 34-43).

22

The procedure for the preparation of the copolymer resin of vinyl chloride and vinyl acetate impregnated with a mixed foaming agent of trichlorofluoromethane and butane was the same as described in Example I, the resin used having a vinyl acetate content, average degree of polymerization P and pore volume Vp as indicated in the table below D owned. The amounts of impregnation with the foaming agent as determined immediately after the preparation and after storage for 1 week at 20 ° C are indicated in the table.

Expandable resin products were prepared by mixing 100 parts of the copolymer resin prepared as described above, impregnated with the mixed foaming agent, 2 parts of a tin-containing stabilizer and 1 part of calcium stearate together with or without the addition of 1 part of talc as nucleating agent, 1 part decomposable foaming agent of an azodicarbon amide compound, sold under the name Celmic 133 by Sankyo Kasei Co., Japan, and one of the acrylic resins E1 and E-2 indicated below in an amount as indicated in Table D.

The acrylic resins used as a foaming conditioner in the tests and designated E-1 or E-2 in the table were the following products, respectively.

E-1: a copolymer resin consisting of 90 wt% methyl methyl acrylate and 10 wt% ethyl acrylate with a reduced viscosity of 10 dl / g at 25 ° C in 0.1 g / 100 ml chloroform solution. E-2: a technical acrylic resin sold under the tradename Paraloid K-120 by Rohm & Haas Co.

The expandable resin products were processed into foamed articles by extrusion molding using the same extruder and under the same operating conditions of the machine as in Example 1, and the foamed articles were tested for bulk density and cell structure with the 7908221 23 cell structure. results shown in Table D were obtained. The evaluation of the cell structure, indicated in the table, was done according to the standards indicated below.

Cell structure A: diameter of the cells not greater than 500 µm.

Cell structure B: diameter of the cells 500 µm to 2000 µm.

The foamed article obtained in Test 40 was very fragile. In Run 43, premature expansion of the resin product occurred while still in the mold, resulting in the appearance of flow marks on the surface of the foamed article.

79 0 82 2 f 24

MOO

rn and o o o es m o. o · _ · O- «« 3 3 CS O - λ Γ- <Γ-Ν m—] · γ-ι ï λ Λ <e

O pel S3 O

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! "·« O O *! ") * I-i i« o <J

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H

O • 'v -e · es o - o <n 300 rn »—i es o«> «te tu -« m

m ·> - o * i-i tu i o o <J

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td M 0) O <U M

te o) £ o no i 2 • U / -s m es na <U 3 (UB * S 00 - · Η ÖO ^ 4->.

0 O) · \ 03 ·· “! 6 4-1 Y-JI-IO

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3 Ό / - * T3 UW

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tu Ito l-i 3 0 r-t pn OU

o u n ο. + j as r-n <u w m co o

μ> 3 g <U CJ CU * H 3 3 3 O

ft ft ai HgeoMWo ^ o> 7908221 25 CO m O _. "_ 1-1 O m m <ü fi" 00 cm ·> * »n <U · *» _

o σ \ co <U * M

* 00 o o

CM <M CM O O

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Λ oO O «« <U (U * M

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cö _____________ - O o o o O o vf co om * * ö ö ^ __

vOOvO <f <U 0) * M

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CM * CTi 00 0) dj * PQ

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σ> o o co 'CO vf O CM O Ό ©

CO O * * Π3 CM CM

<- m fs vO * r-1 I O * · <o w * o

vO

s- / 7 9 0 8 2 2 t

Example V

(Tests 46 - 56).

26

1000 g of the same copolymer resin, consisting of vinyl chloride and vinyl acetate, as used in example II, 2000 g of purified water and 1.0 g of partially saponified polyvinyl alcohol and one or a combination of two were charged into the same autoclave as used in example IV. types of the volatilizable foaming agents indicated in Table E in the amounts also indicated in the Table were added under pressure thereto, followed by stirring at 70 ° C for 8 hours to impregnate the resin with the foaming agent or foaming agents. The amounts of impregnation with the foaming agents are shown in Table E.

Expandable resin products were prepared by mixing 100 parts each of the copolymer resin impregnated with the volatilizable foaming agent, 1 part (tests 46-48) or 3 parts (tests 49-56) of a nucleating agent as indicated in Table E together with or without addition of 6 parts of an acrylic resin (Metablen P551, a product name of Mitsubishi Rayon Co., Japan) as a foam conditioner.

The following nucleating agents were used in the experiments.

• Orben: An organic complex of a colloidal hydrated aluminum silicate with an average particle diameter of about 0.5 µm, a product of Shiraishi Calcium Co., Japan.

Hakuenka 0: a calcium carbonate filler with an average particle diameter of 0.02-30 0.03yum, a product of Shiraishi

Calcium Co., Japan.

Titanium Dioxide A-100: A filler quality titanium dioxide with an average particle diameter of about 0.15-0.25 µm. a product of Ishihara Sangyo Co., Japan.

7908221 27

Aerosil 200: A smoke silica filler with a specific surface area of about 2,200 m / g and an average particle diameter of about 0.012 µm, a product of Nippon Aerosil Co., Japan.

Aerosil 380: A smoke silica filler with a specific surface area of about 380 m / g and an average particle diameter of about 0.002 µg, a product of Nippon Aerosil Co., Japan.

A ^ O ^ C: an alumina filler with an average particle diameter of about 0.005-0.02 µm, a product of Nippon Aerosil Co., Japan.

Barium sulfate 100: a product of Sakai Chemical Co.,

Japan, with an average particle diameter of about 0.6 µm.

Satenton No. 5: a clay product from Tsuchiya Kaolin Co., 20 Japan.

3S Talk: a talc product from Nitto Funka Kogyo Co., Japan.

The expandable resin products thus prepared were processed into foamed articles in the form of a cylindrical rod by extrusion molding with the same extruder and under the same operating conditions as in Example IV, and the foamed articles were tested for bulk density using the table E indicated results were obtained.

30 79 0 8 2 2 t 28 • Η Μ ΟΊ

s ~ \ Ο Ο β β CO

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η + j β φ η οο φ «ρ φ w β Ρ Η φ ο ρΩ ι—] Ö0 r ~ i r — C Ό Ο οο φ βΦ χΐ η φ -3 {> • Η Ί3 · Η Ό β β Ό φ. -U Τ3 Μβ3Φ βΓ0 Ε0 · ητ) Ο Λ · Η Φ · Η β Λ · Η η 13 Β β 06 ββ ^ νη * 3 6 β.Φ · Η 36 006 ^ 5 0 <~ Ι Φ β, α Μ 3 Λ Μ-Ι, Η-Η Φ · Η ·> Φ Φ * Η ι-Η 4-1 * 3 τΗ φ> 3 η 3 & 6 ό η 3> »η ο 6 ο η, β a rö φ φό 4J η ο «^ η φο β ο μ · η · η βο ο ηφοο A> Μ_Μ CO V- 'ίχί & _ο Μ <! C0 bOw 7908221 29 cd λ Μ Ο -3- Ρ.

\ οοο * α> cd Ρ

lil MN I "SO -1-1¾ CO

H ra so

SS

1 — i m & co ra o ra ff o m o o ·> o co -1-1¾ r- O CM CTv S-l co aj *

PH V (U CO

<! <r S o o o rj. M o m p * o + O o «ra sol co

η Μ Μ <f in i-i -i-i -η O

E-i '- ixi ^ ________ ω co So' o cm, ΙΛ pa o + o o «Ai i J, i — I o - CQ - co rj -i-l-i-lp.

<ü t-j w w cd Ό

S H

H

CM I 4J

m S o _ o · ** a 5.

pa OOO “p ra o, cjcn + cQco co -ricwo co cd tn pa w ν_ί Pl rM - · -llf-1 - CO P H-“ pa ra -mo - i - \ t S "at" U .4 -, ¾ m S oo * co cdcdin

pa O + H O CM O -rn-r-i O

O CM fli - - CM *

μ v v i — ï O

<! 7908221

Example VX

(Tests 58-71).

30

A 100 liter capacity autoclave, made of stainless steel and equipped with a stirrer, was charged with 30 kg of a copolymer resin, consisting of 88 wt% vinyl chloride and 12 wt% vinyl acetate, and with an average degree of polymerization. P of about 850 and a pore volume Vp of 0.015 ml / g, 50 kg of purified water, 15 g of a partially saponified polyvinyl alcohol and 6 kg of trichlorofluoromethane 10 and further 3 kg of butane were added under pressure, followed by stirring at 70 ° C for 8 hours to impregnate the resin with trichlorofluoromethane and butane as the volatilizable foaming agents. After the completion of the impregnation, the cooling to room temperature and the removal of the excess foaming agents, the resin was dewatered by centrifugal separation and dried in an air stream at 40-50 ° C. The total amount of the foaming agents in the resin impregnated therewith was 11.8% by weight.

Expandable resin products were prepared by mixing 100 parts of the above-obtained copolymer resin impregnated with the volatilizable foaming agents, 2 parts of a tin-containing stabilizer and 1 part of calcium stearate together with or without talc (tests other than 62) ) in an amount as indicated in Table F or a combination of 0.5 parts of sodium hydrogen carbonate and 0.4 parts of citric acid (Run 62) as a nucleating agent, a decomposable foaming agent and an acrylic resin as a foaming conditioner as indicated in Table F.

The abbreviations used in Table F for the decomposable foaming agents and the acrylic resins are listed below.

AIBN = α, α'-azobisisobutyronitrile PTS = p-toluenesulfonylhydrazine OBS = 4,4, -oxy-bis (benzenesulfonylhydrazide)

DNM = dinitrosopentamethylene tetramine Celmic 133 = see example IV

7908221 31 E-3 = a copolymer resin consisting of 80% by weight methyl methacrylate, 10% by weight butyl acrylate and 10% by weight ethyl acrylate with a reduced viscosity of 5.5 dl / g at 25 ° C E-4 = a copolymer resin, consisting of from 85 wt.% methyl methacrylate 5 and 15 wt.% butyl acrylate with a reduced viscosity of 5.0 dl / g at 25 ° C.

E-5 = a technical acrylic resin, sold under the tradename Paraloid K-I25 by Rohm & Haas Co.

E-6 = a technical acrylic resin, sold under the trade name Paraloid K-l47 by Rohm & Haas Co.

Each of the resin products was processed into a foamed article in the form of a slab by extrusion molding with the same extruder and under the same operating conditions as in Example III and the foamed articles were tested for bulk density, cell structure, appearance, compression strength and other mechanical properties and the thermal conductivity. The determination of the compression strength was carried out according to the method described in ASTM D 1621, and the thermal conductivity was determined according to the method described in JIS A 1413. The results are shown in Table F.

In Runs 70 and 71, premature expansion of the resin product occurred while still in the mold, leading to broken foams and the appearance of flow marks on the surface of the foamed article.

The appearance of the foamed article obtained in Test 69 was also less satisfactory. The cellular structure of the foamed articles was good in all tests with the exception that the foamed article of Test 68 showed a less uniform cellular structure.

30 7908221 32

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u co tl) + j o ss m cm · τ-ι / —v m o co co

votu g (O o i <n o <r CO. - CM

• Η H to "W ·>» n ·> O

cc a) i—> oen mm *>

U SS O.

O

^ s S Λ CO ** "> T — i o 2o 3 0 m o o o co co cm

\ 0 «i Z n + Q)« i | *> ·> ·> ·> * O

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"-" p ss ^ - "O

ss ss m o o co o <r o co ^ ^

* pp «1“ Oto Ht "CO CM

«Θ'- η in ·>« ·> "O

<w / o co mm * o - ^ β and o M o CU ss I m λ η λ i — i t— <o m i — i pu - · ^ o * co

Pu ss tdmmom <1cm vo

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i — i tupnocommo <u S “-s °

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β β CU I

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co o <u cn o o ^ ° ω Min oen and o £.

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r>. o u o vo * · ι-ι cn «o en - ë cn <f i ^ <· _„ ΖΓ r-l — w mo o o - ° o g _. fll P · Λ Λ Λ Λ Ο ^ υ> _ / ο m .οο - «ι ____; __ ° *« „ι-io Ο · η and /« ι ο- and ^ vo ^ ëc oo g „o and o «3 8 w ~ o" and "oooo

CJ ^ n O.

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a

O

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O O 0) OO O

O o o o o er cm

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7908221

Example VII

(Tests 72 -92).

34

In an autoclave with a capacity of 5 liters,. made of stainless steel and equipped with a stirrer, 1000 g of a homopolymeric polyvinyl chloride resin or a copolymer resin consisting of vinyl chloride and vinyl acetate, as indicated in Table G below, were charged, 2,000 g of purified water and one or a combination of two kinds volatilizable foams as indicated in the table in the amounts also indicated in the table, if necessary under compression, followed by stirring at 70 ° G for 8 hours to impregnate the resin with the volatilizable foaming agent. After the completion of the impregnation, the cooling to room temperature and the removal of the excess foaming agent, the resin was dewatered by filtration and dried in an air stream at 40-50 ° C for about 5 hours. The resins thus obtained were tested for the amount of foaming agent contained therein to give the results shown in Table G. Furthermore, the resins were kept at 20 ° C for one week in order to investigate the loss by spreading during storage. The amount of foaming agent reduction ranged from 6 to 9% for each of the resins.

Expandable resin products were prepared by mixing 100 parts of the resin obtained above, impregnated with the volatilizable foaming agent, 2 parts of a tin-containing stabilizer and 1 part of calcium stearate together with or without addition of a nucleating agent, a decomposable foaming agent and an acrylic resin (E1) as a foam conditioner, as indicated in Table G below, and the resin products were each processed into a foamed article in the form of a cylindrical rod by extrusion molding. The operating conditions of the extruder are listed below.

Operating conditions of the extruder: 79 0 6 *?. ^ 35

Diameter of the screw 25 mm

Length of the screw 750 mm

Compression ratio of the screw 3.0

Die 8 mm diameter of the 5 opening and 100 mm land length

Screens one with 80 mesh opening and one with 100 mesh opening

Temperature of the cylinder Cj = 60 - 120 ° C

10 C2 = 100-160 ° C

C3 = 120-180 ° C

Temperature of the mold 100 - 130 ° C

Rotation speed 50 r.p.m.

The foamed articles 15 thus obtained were examined for the bulk density and the condition of the cell structure, the results indicated in Table G being obtained.

For the abbreviations of the volatilizable and decomposable foaming agents, reference is made to the previous examples.

The criteria for the cell structure A and B are. indicated in example IV and the cell structure C means that the cells of the foams have a diameter of more than 1 mm and the structure is coarse and not uniform.

The foamed article obtained in Run 87 was particularly fragile and the foamed Runs 91 and 92 exhibited significant shrinkage after formation.

30 7908 221 36 -

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a) r £

Cti _ / - \ / ~> Η σ o o m So o _ co ocNpum + o r- »d 13 o ·> Ο · —1 tD CM * 0) pq» o p-

- «. Ο H w ffl ^ CM 4) Η p- · "U

60 <1 w - · 00 o o o S o o oo - Ocopmio + O eo

00OO '-' pCM '' ^ i / -N

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o «J ·> 4) O CM

4J -> o) «pfl - tiO o o o

00 i “* CF \ / C — N / —N

CM LO S Ο O

i— »pq UO Ο O

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·> EH ^ P 'OS r-l> - ö “0 O CÖ o as · -

+ J ·> 4) «P

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Example VIII

(Tests 96-109).

39

Into an autoclave with a capacity of 100 liters, made of stainless steel and equipped with a stirrer, 30 kg of a copolymer resin, consisting of 90% by weight of vinyl chloride and 10% by weight of vinyl acetate, and with an average degree of polyinerization of 1050 were charged. and a pore volume of 0.023 ml / g, 50 kg of purified water, 15 g of a partially saponified polyvinyl alcohol and 6 kg of trichlorofluoromethane and further D 3 kg of butane were added thereto under compression followed by stirring at 70 ° C for 8 hours to make the resin to be impregnated with trichlorofluoromethane and butane as volatilizable foaming agents. After the completion of the impregnation, the cooling to room temperature and the removal of excess skewers, the resin was dewatered by centrifugal separation and dried in an air stream at 40-50 ° C. The total amount of trichlorofluoromethane and butane in the thus impregnated resin was 12.0 wt%.

Expandable resin products were prepared by mixing 100 parts of the above-prepared resin each time, impregnated with the volatilizable foaming agents, 2 parts of a tin-containing stabilizer and 1 part of calcium stearate together with or without the addition of 1 part of talc as a nucleating agent. 5 dl of Celmic 133 as a decomposable foaming agent and one of the acrylic resins E-7 to E-13 in an amount as indicated in Table H below, and the resin products were processed into foamed articles in the form of a slab using an extruder which was operated under the conditions indicated below.

The nucleating agent was omitted in Trials 106 and 107 and the decomposable foaming agent was omitted in Trials 106 and 108.

7908221 40

Acrylic resins E-7 = a copolymer resin, consisting of 90 wt% methyl methacrylate and 10 wt% ethyl acrylate and with a reduced viscosity of 4.5 dl / g at 25 ° C.

E-8 = a copolymer resin, consisting of 90 wt% methyl methacrylate and 10 wt% ethyl acrylate, and with a reduced viscosity of 7.0 dl / g at 25 ° C.

10 E-9 = a copolymer resin, consisting of 90 wt% methyl methacrylate and 10 wt% ethyl acrylate, and with a reduced viscosity of 11.0 dl / g at 25 ° C.

E-10 = a copolymer resin, consisting of 90% by weight of methyl methacrylate and 10% by weight of ethyl acrylate, and with a reduced viscosity of 15.3 dl / g at 25 ° C.

E-11 = a copolymer resin, consisting of 95% by weight of methyl methacrylate and 5% by weight of butyl acrylate, and with a reduced

viscosity of 10.7 dl / g at 25 ° C

E-12 = a copolymer resin consisting of 80% by weight methyl methacrylate, 5% by weight ethyl acrylate, 5% by weight butyl acrylate and 10% by weight butyl methacrylate, and with a

reduced viscosity of 11.0 dl / g at 25 ° C

E-13 = a copolymer resin, consisting of 80 wt% methyl methacrylate and 20 wt% ethyl acrylate, and with a reduced viscosity of 2.0 dl / g at 25 ° C.

The operating conditions of the extruder are indicated below.

7908221 41

Diameter of the screw 65 mm

Length of the screw 1950 mm

Compression ratio of the screw 3.0

Die 100 mm width and 5 8 mm height

Screens one with SO.mesh opening and

one with 100 mesh opening Cylinder temperature Cj = 95 ° C

C2-130 ° C

C3 = 150 ° C

Temperature of the mold 120 ° C

Rotation speed 20 r.p.m.

The foamed articles thus obtained were tested for bulk density, cell structure, compression strength as determined by the method described in ASTM D 1621, and flexural strength as determined by the method described in ISO R 1209, wherein the results shown in Table H were obtained.

In Runs 104 and 105, premature expansion of the resin product occurred while it was still in the mold, which led greatly to broken foams and to shrinking of the foamed article after formation with a less uniform cell structure. The foamed articles obtained in Runs 108 and 109 were also less uniform in cell structure, although no premature expansion of the resin product occurred.

As can be seen from the results indicated in the table, an acrylic resin with a higher reduced viscosity can give the advantages of the possibility of reducing the amount of acrylic resin as well as of a greater retention of the gas for the build-up of the foams, stabilization of the foam cells and reduction of shrinkage. On the other hand, when the acrylic resin used has a low reduced viscosity or the amount of the acrylic resin is insufficient, the foams are severely broken, resulting in a strong shrinkage of the foams after formation and a coarser cell structure of the foams.

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Example IX

(Tests 110-117).

Into an autoclave with a capacity of 10 liters, made of stainless steel and equipped with a stirrer, 3 kg of a homopolymeric polyvinyl chloride resin or a copolymer resin of vinyl chloride and vinyl acetate were added, with the vinyl acetate content of the resin is indicated in table I below, with an average degree of polymerization and a pore volume as indicated in the table, 5 kg of purified water, 1.5 g of a partially saponified polyvinyl alcohol and 600 g of trichlorofluoromethane and further 300 g of butane were added thereto under pressure, followed by stirring at 70 ° C for 8 hours to impregnate the resin with trichlorofluoromethane and butane as the volatilizable foaming agents. After the completion of the impregnation, the cooling to room temperature and the removal of the excess foaming agents, the resin was dewatered by filtration and dried in an air stream at 50 ° C for 5 hours. The total amount of the foaming agents in the resin so impregnated is shown in the table.

Expandable resin products were prepared by mixing 100 parts of the above-prepared resin each time, impregnated with the volatilizable foaming agents, 2 parts of a tin-containing stabilizer, 1 part of calcium stearate, 1 part of talc as a nucleating agent, and 10 parts of one of the acrylic resins. E-7, E-10 and E-13 (see Example VIII) as a foam conditioner and the resin products were processed into foamed articles in the form of a cylindrical rod in the same manner as in Example VII. The bulk density and cell structure condition of these foamed articles are shown in Table I. The foamed articles obtained in Runs 115 and 116 showed a slight shrinkage after formation.

As can be seen from the results shown in Table I, when the vinyl chloride-based resin has a higher degree of polymerization, the use of an acrylic resin having a correspondingly greater reduced viscosity is desirable and foamed articles of high expansion and uniformity cell structure can even be obtained with a resin with a small vinyl acetate content, which otherwise requires a relatively high processing temperature, by suitable selection of the acrylic resin as a foam conditioner.

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Example X.

(Tests 118-133).

-47

Into an autoclave with a capacity of 5 liters, made of stainless steel and equipped with a stirrer, 1000 g of a homopolymeric polyvinyl chloride resin or an copolymer resin of vinyl chloride and vinyl acetate, of which the vinyl acetate content is indicated, were introduced. Table J below, with an average degree of polymerization and a pore volume as indicated in the table, 2000 g of purified water, 1.0 g of a partially saponified polyvinyl alcohol and 150 g of trichlorofluoromethane and further 100 g of butane were added thereto under pressure, followed by stirring at 70 ° C for 8 hours to impregnate the resin with trichlorofluoromethane and butane as volatile foaming agents. After the completion of the impregnation, the cooling to room temperature and the removal of the excess foaming agents, the resin was dewatered by filtration and dried in an air stream at 40-50 ° C for about 5 hours.

The total amount of the foaming agents in the resin impregnated therewith was determined to give the results shown in Table J below. The loss of the foaming agents by extrusion during storage at 20 ° C for one week ranged from 6 to 9% for each of the resins.

Expandable resin products were then prepared by mixing 100 parts of the above-prepared resin each, impregnated with foaming agents, 2 parts of a tin-containing stabilizer and 1 part of calcium stearate together with or without addition of a nucleating agent of the type shown in Table J in an amount as indicated in the table, a decomposable foaming agent as indicated in the table and a copolymer resin S1, consisting of 70 wt.% styrene and 30 wt.% acrylonitrile, and with a reduced viscosity of 12.0 dl / g at 25 ° C as styrene-based foam-conditioning resin in an amount as indicated in the table and the resin products were processed into foamed articles in the form of a cylindrical rod by extrusion molding. The operating conditions of the extruder 79 0 8 2 2 t 48 machine were almost the same as in Example VII.

The foamed articles thus obtained were tested for bulk density and cellular structure to give the results shown in Table I.

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a \ o o * - · co * wcoa λ _ I — 3 T — i T— <iTj O Λ t — I Λ g CO O O <£ _ r-> * o cd t— * - ^ Λ * 2 *.

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Example XI

(Tests 134-143).

51

1000 g of a copolymer resin consisting of 90% by weight of vinyl chloride and 10% by weight of vinyl acetate, with an average degree of polymerization, were placed in an autoclave with a capacity of 5 liters, made of stainless steel and equipped with a stirrer. of 850 and a pore volume of 0.015 ml / g, 2000 g of purified water and 1.0 g of a partially saponified polyvinyl alcohol and one or a combination of two kinds of volatilizable foaming agents were added or supplied under pressure as indicated in Table K below followed by stirring at 70 ° C for 8 hours to impregnate the resin with the foaming agent.

After the completion of the impregnation, cooling to room temperature and removal of the excess foaming agent, the resin was dewatered by centrifugal separation and dried in an air stream. The amount of foaming agent present in the resin impregnated therewith is shown in Table K.

Expandable resin products were prepared by mixing 100 parts of the above obtained resin each time. impregnated with the foaming agent, with talc as the nucleating agent, Celmic 133 as the decomposable foaming agent and the styrene-based copolymer resin Sl as the foaming conditioner, each in an amount as indicated in Table K, and the resin products were processed into foamed articles in the same manner as described in the previous example. The bulk density of the foamed articles thus obtained is shown in Table K. The foamed articles of Runs 141 and 142 showed significant shrinkage after formation.

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a o M3 o o m co WO ·> *> ·> o - o co mcM— m «H ^ - O - _____ _____________

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CD ____________

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Pr-1 ÖO1-4-— H CU P O

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CU> p! H U ^ P go co-HUP

o HP PP lp P P Hl O co H

H cu o go cd tu'- 'cdco p cu cu P> CO HCO PO B ^ CO ÖO ^ 7® 0 8 2 2 f 53

Example XII

(Tests 144-150).

In an autoclave with a capacity of 100 liters, made of stainless steel and equipped with a stirrer, 30 kg of a cpolymer resin, consisting of 90 wt.% Vinyl chloride and 10 wt.% Vinyl acetate, and with an average degree of polymerization of 1050 were charged. and a pore volume of 0.023 ml / g, 50 kg of purified water, 15 g of a partially saponified polyvinyl alcohol and 6 kg of trichlorofluoromethane and further 10 kg of butane were supplied under pressure, followed by stirring at 70 ° C for 8 hours to make the resin to be impregnated with trichlorofluoromethane and butane as volatilizable foaming agents. After the completion of the impregnation, cooling to room temperature and removal of the excess foaming agents, the resin was dewatered by centrifugal separation and dried in an air stream at 40-50 ° C. The total amount of the foaming agents in the resin impregnated therewith was 12.0% by weight.

Expandable resin products were prepared by mixing 100 parts of the copolymer resin obtained above each time, impregnated with the foaming agents, 2 parts of a tin-containing stabilizer, 1 part of calcium stearate, 1 part of talc as a nucleating agent, 0.5 part Celmic 133 as a decomposable foaming agent and one of the styrene-based copolymer resins S-2 to S-5 as described below as a foaming conditioner in an amount as indicated in Table L below and the resin products were processed into foamed articles in the mold of an extrusion molding wafer with an extruder operated under the same operating conditions as in Example VIII.

The foamed articles thus obtained were tested for bulk density, cell structure, compression strength and flexural strength to give the results shown in Table I. In Runs 149 and 150, a premature expansion of the resin product occurred while still in the mold, resulting in broken foams and significant shrinkage of the foamed articles after molding.

79 0 8 2 2 t 54

Styrene-based copolymer resins.

S-2 = a copolymer resin, consisting of 70 wt% styrene and 30 wt% acrylonitrile, and with a reduced viscosity of 2.0 dl / g at 25 ° C.

S-3 = a copolymer resin, consisting of 70 wt% styrene and 30 wt% acrylonitrile, and with a reduced viscosity of 4.0 dl / g at 25 ° C.

S-4 = a copolymer resin, consisting of 70 wt% styrene and 30 wt% acrylonitrile, and with a reduced viscosity of 10.0 dl / g at 25 ° C.

S-5 = a copolymer resin, consisting of 75 wt.% Styrene and 25 wt.% Acrylonitrile, and with a reduced viscosity of 14.6 dl / g at 25 ° C.

As is apparent from the results set forth in Table 1, a styrene-based copolymer resin having a greater reduced viscosity as a foam conditioner can provide the benefits of improved gas retention or foam build-up, foam stabilization and reduced shrinkage, even when the amount of the admixed resin is relatively small, while the use of a resin with a smaller reduced viscosity results in broken foams and a strong shrinkage after formation, resulting in a coarser cell structure, especially when the amount added is insufficient.

7908221 55 I ✓'s i.

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00 3 W

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μ cd * rl Ü 3 3 O O 3 pH 33 Η 01 p <ilO O ^? 79 0 82 2 t

Example XIII

(Tests 151-156).

56

Into an autoclave with a capacity of 10 liters, made of stainless steel and equipped with a stirrer, 3 kg of a homopolymeric polyvinyl chloride resin or a copolymer resin of vinyl chloride and vinyl acetate, of which the vinyl acetate content is indicated in table M below, were introduced. , with an average degree of polymerization and a pore volume as indicated in the table, 5 kg of purified water, 1.5 g of a partially saponified polyvinyl alcohol and 600 g of trichlorofluoromethane and further 200 g of butane were supplied under pressure, followed by stirring at 70 ° C for 8 hours to impregnate the resin with trichlorofluoromethane and butane as volatilizable foams. After the completion of the impregnation, cooling to room temperature and removal of the excess foaming agent, the resin was dewatered by filtration and dried in an air stream at 50 ° C for 5 hours. The total amount of the foaming agents in the resin impregnated therewith is shown in Table M.

Expandable resin products were prepared by mixing 100 parts of the resin obtained above each time, impregnated with the volatilizable foaming agents, 2 parts of a tin-containing stabilizer, 1 part of calcium stearate, 1 part of talc as a nucleating agent, 0.5 part of Cell 133 as a decomposable foaming agent and a styrene-based resin of the kind indicated in the table as a foaming conditioner in an amount as indicated in the table and the resin products were processed by extrusion molding into foamed articles in the same manner as in Example X The bulk density and cell structure condition of these foamed articles are shown in Table M. The foamed article of Run 155 exhibited some shrinkage after formation and significant foam breakage occurred on Run 156, which resulted in a significant shrinkage of the foamed article after formation.

As can be seen from the results shown in Table M, the styrene-based resin as a foam conditioner desirably should have a greater reduced viscosity than 790822! 57 the vinyl chloride-based resin has a relatively high degree of polymerization. A foam with a high expansion and a uniform cell structure can even be obtained with a vinyl chloride-based resin without vinyl acetate or with a relatively small vinyl acetate content, otherwise requiring a relatively high processing temperature, by suitable selection of the foam-conditioning agent.

On the other hand, a copolymer resin with a relatively low degree of polymerization can give a high expansion foamed article, even with a styrene-based resin as a foam conditioner with a relatively low reduced viscosity, when the vinyl acetate content in the copolymer resin is high, but a foamed article with high expansion is difficult to obtain with a copolymer resin, the vinyl acetate content of which is low.

79 0 8 2 2 f 58

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Claims (16)

A resin product, which can be expanded by heating into a foamed article, characterized in that it comprises (a) 100 parts by weight of a polyvinyl chloride-based resin with an average degree of polymerization of at most 2000 and a pore volume of at most 0.20 ml / g and (b) at least 1 part by weight of a volatilizable foaming agent selected from aliphatic hydrocarbon compounds and aliphatic halohydrocarbon compounds with a boiling point not exceeding 90 ° C and impregnated into the resin on a polyvinyl chloride basis. 2. A resin product, which can be expanded by heating into a foamed article, characterized in that it comprises (a) 100 parts by weight of a polyvinyl chloride-based resin with an average degree of polymerization of at most 2000 and a pore volume of not more than 0.20 ml / g, (b) at least 1 part by weight of a volatilizable foaming agent, selected from aliphatic hydrocarbon compounds and aliphatic halohydrocarbon compounds with a boiling point not exceeding 90 ° C and impregnated into the polyvinyl chloride-based resin (c) 0.5-30 parts by weight of a foaming conditioner selected from styrene-based acrylic resins and resins, and (d) 0.01-20 parts by weight of a nucleating agent. Resin product according to claims 1 or 2, 25, characterized in that the polyvinyl chloride-based resin is a copolymer resin consisting of 60-97% by weight of vinyl chloride and 40-3% by weight of vinyl acetate. Resin product according to claims 1 or 2, characterized in that the polyvinyl chloride-based resin has an average degree of polymerization of at least 300. Resin product according to claim 2, characterized in that the foam conditioning agent has a reduced viscosity of at least 3.0 dl / g as measured in a chloroform solution with a concentration of 0.1 g / 100 ml at 25 ° C. Resin product according to claim 2, characterized in that the nucleating agent is an inorganic powder 7908221 material with an average particle diameter of at most 30 µm. Resin product according to claim 2, characterized in that the nucleating agent is a combination of an acid, which is solid at room temperature, and a carbonate or hydrogen carbonate of sodium, potassium or ammonium. Resin product according to claim 7, characterized in that the acid which is solid at room temperature is boric acid or an organic acid selected from citric acid, tartaric acid and oxalic acid. Resin product according to claim 2, characterized in that the acrylic resin is a polymethyl methacrylate. Resin product according to claim 2, characterized in that the acrylic resin is a copolymer resin consisting of methyl methacrylate and at least one acrylic ester selected from alkyl acrylates and alkyl methacrylates other than methyl methacrylate. Resin product according to claim 10, characterized in that the methyl methacrylate content in the copolymer resin is 60-95% by weight. Resin product according to claim 2, characterized in that the styrene-based resin is a copolymer resin consisting of 90-40% by weight of styrene and 10-60% by weight of a styrene copolymerizable comonomer. Resin product according to claim 12, characterized in that the styrene copolymerizable comonomer is acrylonitrile. Resin product according to claim 2, characterized in that a decomposable blowing agent is additionally present in an amount of not more than 5 parts by weight. Foamed articles made using the resin product according to claims 1-14. 16. Products and methods as described in the description and / or examples. 35 ✓ 1 7908221 / ί i