DE2018537C3 - Process for the production of foams on the basis of vinyl chloride polymers - Google Patents

Description

The invention relates to a method for producing soft or hard foams on the basis of polyvinyl chloride with the help of a new propellant, as well as on that after this Process obtained products.

It's generally known. To add organic substances such as biuret to polyvinyl chloride for the production of foams and then preheat the mixture. The organic R ¹ -NH-C-N decompose

in which X is an oxygen or sulfur atom or the imino group, R ^{1 is} a hydrogen atom, an alkyl group with less than 6 carbon atoms, an acyl group with less than 5 carbon atoms or a carbamyl group optionally substituted with alkyl groups with less than 4 carbon atoms, R ² for a hydrogen atom or an alkyl group with less than 6 carbon atoms and R ³ for a hydrogen atom, an alkyl group with less than 6 carbon atoms, an acyl group with less than 5 carbon atoms, one optionally with

'ό

Alkylgruppan a carbamyl group substituted with fewer than A carbon atoms or a saturated aliphatic ester group with fewer than 6 carbon atoms and

b) contains an alcohol having 1 to 14 carbon atoms, which is an optionally halogen-, alkyl-, alkoxy-, phenoxy- or amino-substituted aliphatic alcohol or an aromatic alcohol or an optionally alkyl-substituted cycloaliphatic alcohol, a molar ratio of Alcohol to nitrogen derivative of carbonic acid complies with 0.1 to 2 and the propellant mixture is used in an amount of 2 to 100% by weight, based on the vinyl chloride polymer.

Vinyl chloride polymers in the context of the description are the homopolymers, copolymers, post-chlorinated Polymers of vinyl chloride, their mixtures with each other or with other compatible polymers, such as polypropylene, polyethylene, polystyrene, polyurethane, vinyl acetate-ethylene copolymer and acrylonitrile-butadiene-styrene copolymers. When mixed with other compatible polymers, the proportion of vinyl chloride polymer should be 50 to 99 wt .-% of the total mixture. The vinyl chloride copolymer should be at least 50% by weight consist of vinyl chloride units; vinyl esters such as vinyl acetate come as comonomers, Alkyl acrylates and alkyl methacrylates, fumaric acid esters, maleic acid esters, chlorofumaric acid esters, chloromaleic acid esters, Alkyl vinyl ether, vinylidene chloride. Vinyl pyridine, ethylene, propylene, acrylonitrile and vinyl alcohol in Ask.

The copolymer can also be a vinyl chloride homopolymer or copolymer made with butadiene and acrylonitrile, butadiene and an alkyl methacrylate and / or alkyl acrylate, with butadiene, an alkyl acrylate, styrene and a crosslinking agent, such as divinylbenzene. is grafted.

The vinyl chloride polymers and copolymers are prepared in any known manner: by Bulk polymerisation, suspension polymerisation, polymerisation in fine suspension or microsuspension or by emulsion polymerization.

For the production of post-chlorinated or perchlorinated vinyl chloride polymers, the one in the is particularly suitable FR-PS 14 39 877 and additional PS 89 193 described method.

The nitrogen derivatives of carbonic acid that correspond to the formula given include urea, Biuret, thiourea, acetylurea, diacetylurea, triuret, guanidine, lower alkyl allophanates, lower alkyl carbamylallophanates, N-methyl-N'-acetylurea and N-methyl-N ', N'-dimethylurea.

The aliphatic, aromatic and cyclop'iphatic alcohols used according to the invention can primary, secondary and tertiary saturated and unsaturated monoalcohols as well as the saturated and unsaturated Polyolein.

Examples of monoalcohols corresponding to this definition are methanol, ethanol, propanol, butanol, amyl alcohol, hexanol, 2-chloroethanol, 2-methoxyälhanol, 2-butoxyethanol, 2-phenoxyethanol, allyl alcohol, buten-2-ol, propargyl alcohol, benzyl alcohol, phenylethanol, Diphenylcarbinol, cinnamon alcohol and cyclohexanol.

Examples of polyols are glycol, propylene glycol, trimethylene glycol. 1,4-butanediol, l-chloro-2,3-propanediol, 3-methoxy-l ^ -propanediol, glycerine, erythritol, pentaerythritol and sorbitol

According to a further development of the method

contains the additive mixture additionally at least a carboxylic acid from the following groups, the acid content in a mixture of alcohol and acid up to Mol% can make up:

a) Saturated aliphatic mono- and dicarboxylic acids with 1 to 18, preferably 1 to 8 carbon atoms, which optionally with at least one Chloraton-i, an alkyl, aryl, aryloxy, cyano or chloraryloxy group are substituted, for example Formic acid, oxalic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, Phenylacetic acid, dichlorophenoxyacetic acid, malonic acid, succinic acid, glutaric acid and adipic acid;

b) unsaturated aliphatic mono- or dicarboxylic acids with 3 to 12, preferably 3 to 6 carbon -

atoms and a double bond or triple bond, in ικφ- or jS.y-position, which are optionally substituted with at least one halogen atom or a lower alkyl radical, a phenyl or phenoxy group, for example acrylic acid, crotonic acid, methacrylic acid, cinnamic acid, propargylic acid, maleic acid, fumaric acid and itaconic acid;

c) aromatic mono- or dicarboxylic acids, optionally substituted with at least one Halogen atom or an alkyl group such as benzoic acid, toluic acid, phthalic acid and naphthalic acid;

d) aliphatic oxycarboxylic acids having 2 to 12, preferably 2 to 7 carbon atoms, one or two OH groups and one or two COOH groups, such as glycolic acid, lactic acid, 2-hydroxybutyric acid and oxaloacetic acid;

e) aromatic oxycarboxylic acids with one or two OH groups and one or two COOH groups, such as salicylic acid, m- and p-hydroxybenzoic acid, p-hydroxyphenylacetic acid and hyJroxyphthalic acid.

The molar ratio of alcohol and optionally

Carboxylic acid to nitrogen derivative of carbonic acid in the propellant mixture according to the invention depends on the nature of the components and is preferably 0.2 to 1.5.

The decomposition temperature of the propellant mixture according to the invention is above the gel temperature of the Vinyl chloride polymers or is at least the same.

The blowing agent mixture is preferably added to the vinyl chloride polymer in an amount of from 2 to 40% by weight, based on the polymer.
Depending on whether a rigid foam or a more or less soft cellular product is desired, the vinyl chloride polymer is mixed with up to 150% by weight of a common plasticizer. These are above all

Butyl benzyl phthalate, dioctyl phthalate,
Dibutyl phthalate, dicapryl phthalate,
Dinonyl phthalate; Dioctyl adipate, didecyl adipate;
Dibutyl sebacal, dioctyl sebacate; Tricresyl phosphate, trioctyl phosphate, trixylyl phosphate,
Octyl diphenyl phosphate; chlorinated paraffins;
epoxidized oils and esters; polymers
Plasticizers such as adipic acid or polyester

sebacic acid and plasticizers which are solid at room temperature, such as polymethacrylates and polymethyl methacrylates, polyacrylates and Polyäthylmethacrylate, Po.'ybutylacrylate and Polybutyl methacrylate and the fatty alcohols.

Conventional Vei working methods, such as compression molding, Sprouting, extrusion, calendering, coating mixed together, gelled, deformed and missed " The various process steps can be carried out separately from one another or be combined with each other; for example, haying and foaming, gelling and deforming or combined shaping and foaming

The propellant mixture using the invention can also follow the vinyl chloride polymer added to the gelation.

When processing by compression molding, emulsion polymerization or Polymerisation produced in microsuspension

. ^y . . -jn "i." iM used after mixing

VinyiUIIIUI IU-I uijiiiviu. .... v _.

Lubricants are added.

The neutral or basic lead salts are mentioned as stabilizers: carbonates, sulfates, phosphites, Silicates and stearates; the salts of calcium, cadmium, barium, zinc, lithium and strontium especially the stearates, octoates, and laurates; the tin

"' ¹ ^ ¹ - ltin

how

Crosslinkable plasticizers can also be used, such as diallyl phthalate ethylene glycol mono- or dimethacrylate propylene glycol monomethacrylate or dimethacrylate or unsaturated polyester, with Which after crosslinking foams with noticeably improved dimensional stability in the warmth

will receive «. . Polymerization w ι «· ~ -—ι ° ■■ -

The crosslinkable plasticizers are used in quantities of "Florid polymer". After mixing up to 25% by weight, based on the vinyl chloride po- <5 njjcn ^ ^ _ρ ^ _{die (Jann deformt und untef}

lymer, used _ temperature and time conditions that are pressed

In addition to the plasticizers, the _{fibers can also be used} . The molding obtained is after

Vinyl chloride polymers with conventional stabilizers and _{AbkQhlen and Ent} f _or men with either hot air ■ · ^J - ^ _{t he m} i steam or in a hot Wassar-

or oil bath or by IR irradiation, high frequency or Ultra high frequency is expanding

For processing by extrusion. Injection molding and calendering becomes a vinyl chloride polymer

auem aic oic «» a _lc , _w »- -_ uses that by polymerization in the mass, in

bonds: dilaurates and dimaleinates of dibutyotin 25. ■ Microsuspension or in emulsion

and dioctyltin and mercapto compounds such as suspensio, _. . _

Thiooctyl tin or thiobutyl tin; Zinc oxide and / or

Urea and / or biuret (French patent specification

14 75 865). The stabilizers are used in amounts of üi

up to 8% by weight based on the V. nylon-chloride

° Di'e ^iei nature and amount of added

L / IC DCSUlallciiiiwi unu ... * - .. _e - ^.

Lubricant depends on the chosen processing ;; proceed from. Stearic acid, neutral or basic lead stearates, ethyl palmitate and paraffin waxes are mentioned. Esterwachse, in quantities of 0.1 to 3 wt / 0 added, based on the vinyl chloride-Poly ^m in some cases, it is advantageous to incorporate other conventional aids in vinyl chloride polymers; these are, for example, fillers. Nucleating agents, structure regulators, crosslinking agents and

Suspension, 1Π IVIIlU V »^^ ..—. · -— -..-...- ..,." "

was produced. The viscosity number of this polymer can be high if a soft foam is desired; it must be low if one , 0 rigid foam is to be produced.

When extruding the mixture into a Abandoned extruder and then expanded the extruded profile as indicated

In injection molding, the mixture is made using a screw press or a piston press, the gelled product is injected into a mold and the The molding is foamed as indicated above after cooling and demolding. The foaming can also be used take place immediately in the form.

During calendering, the components become one another be mixed, gelled and standardized on it Sheets or sheets drawn and also foamed as indicated

F. If the processing is carried out by coating or plastisol, a or polymerisation in vinyl chloride polymer ver-All components become a paste merges gelling and expanding

ruuMui.c w. _c Chalk, kaolin, silica. Carbon blacks are sometimes advantageous, but their amount should not be more than 50% by weight, preferably less than 20% by weight of the vinyl chloride polymer.

Nucleating agents are not absolutely necessary, but can be added, for example an azover "-" ^ _Durc hg "ang by""

bond, such as azodicarbonamide fP ™ ^ ¹ ^ ™ ¹ ^ ⁵ ° T _to n _a uch _m U pul / erflmigen mixtures coated Banumazod.carboxylate or carbon black:; | «_Quantity» Jl M5 can jmch ^ ^ P. ^ ^^ ^ ^ _Suspension .

or bulk polymerization produced vinyl chloride polymer used

The foams obtained according to the invention can have closed and / or open cells, depending according to the recipe used, processing method and conditions for foaming. The diameter of the Cells and their wall thickness depend on the same parameters.

With the aid of the propellant mixture according to the invention, numerous, very different

55

bariuina / uuiLiii uuA ^ iai vjuv-i ixuw, ..... _c

Up to 1.5% by weight of the vinyl chloride polymer

Condensation products are primarily used as structural regulators from ethylene oxide and fatty acids and analogous products in question, which in amounts of 0.05 to 1 % By weight, based on the vinyl chloride polymer, are used.

All crosslinkable substances with vinyl chloride polymers come into consideration as crosslinking agents compatible are, for example, an ethylene-vinylaceta'-copolymer, one grafted with butadiene and acrylonitrile Polyvinyl chloride and the crosslinkable plasticizers mentioned above. These crosslinking agents are used in Amounts of from 0 to 25 weight percent of the vinyl chloride polymer are used. The crosslinking takes place on chemical Paths in any known way; it can also be brought about by irradiation.

The various components are using

I reiUllllllcigciiiia »- !!" ·. · »■■■■ - ■ - ■■ -

Manufacture foam products, for example:

thin (<5 mm) flexible foams with a high volume weight (> 0.2 g / cmty thick (5 to 100 mm) flexible foams with a low volume weight (<0.2 g / cm ³ ),

thick (5 to 100 mm) rigid foams in the entire possible density range (0.025 to 0.85 g / cm ³ ).

The foams produced according to the invention on the basis of vinyl chloride polymers can be found in a wide variety Application: for heat and sound insulation. ; ils connecting parts. Leatherette. Documents for Floor coverings, for upholstery, in building, in Furniture manufacture and as packaging materials.

The invention is explained in more detail by means of the following examples.

Example 1 ₍

In a plastisol mixer were placed at room temperature:

200 g polyvinyl chloride, with a viscosity number 180, measured according to the French standard T 51-013, produced by emulsion polymerization,

32.4 g urea,
18.4 g of pentaerythritol and
2 g zinc oxide.

Mix for 15 minutes, add 70 g of butyl benzyl phthalate and mix for a further 10 minutes; it a viscous putty-like paste was obtained.

This paste was placed in a cylindrical mold with an inner diameter of 7 cm and a height of 1 cm at 180 ° C under a pressure of 100 bar for 50 minutes pressed. It was then cooled to room temperature and kept under the same pressure for a further 20 minutes.

The molding was demolded and allowed to rest for 20 minutes before being immersed in boiling water for 15 minutes was expanded.

A flexible foam with a density of 0.21 g / cm ^{3 was obtained} .

40

Example 2

It was according to Example 1, but with 12 g of urea instead of 32.4 g and with 7.2 g of pentaerythritol and 15.2 g Adipic acid worked instead of 18.4 g of pentaerythritol.

A flexible foam with a density of 0.35 g / cm ^{3 was} obtained.

B is ρ ie 1 e 3 and 4 _J0

The following were mixed:

1000 g copolymer of vinyl chloride and vinyl acetate, containing 15% vinyl acetate units, produced by suspension polymerization, viscose 60 (French standard T 51-013), 30 g dibasic lead stearate, 10 ε dibasic lead phosphite

The mixture was kneaded in a roller mixer at 80 ° C. for 10 minutes until gelled. It was further kneaded and a mixture of 160 g of urea and those given in the following table Polyols added; kneading was then carried out again for 10 minutes.

A film was drawn from the mass and allowed to cool on a flat surface. This was followed by the Oven foamed at 200 ° C. for 12 minutes.

Case-polyol
game

Art

Foam

Amount of space procurement

weight fenheil
gg / cm ¹

3 Pentaerythritol 92 0.2 hard 4th Sorbitol 91 0.2 hard

Example 5

It was according to Example 3, but with 60 g of urea instead of 160 g and with 36 g of pentaerythritol and 60 g Fumaric acid worked instead of 92 g of pentaerythritol.

A rigid foam with a density of 0.3 g / cm ^{3 was} obtained.

Test report

A comparison test was carried out against the method of DT-PS 8 51 848 and the Effect of the known propellant mixture of urea and oxalic acid with one according to the application Propellant mixture of urea and a polyalcohol compared.

Carrying out the experiment

The procedure was as in Example 1 of the application, with the modification that instead of 18.4 g of pentaerythritol, the equimolar amount of oxalic acid, ie 23.6 g, was used. With the propellant mixture of urea and oxalic acid, a semi-rigid foam was obtained which had a very irregular and partially collapsed cell structure and a density of 0.6 g / cm ³ .

According to Example 1 of the application, on the other hand, the combination of urea and pentaerythritol gave a flexible foam with a density of 0.21 g / cm ³ which had a fine, regular and non-collapsed cell structure.

The foams obtained according to Examples 2 to 5 of the application are also distinguished from the prior art by a lower density and by a regular and non-collapsed cell structure.

It was by no means foreseeable that such Foams with a low volume weight and a fine, regular structure would be obtained if one were in the dei known propellant combination which replaces oxalic acid with an alcohol such as pentaerythritol or sorbitol

Claims (2)

Patent claims: 1. Process for the production of foams based on vinyl chloride polymers under Use of a nitrogen derivative of carbonic acid and another organic compound containing propellant mixture, wherein the vinyl chloride polymer with the propellant and optionally Plasticizers, stabilizers and other common additives are mixed together to form the mixture is gelled, deformed and foamed, thereby characterized in that a propellant mixture is used which a) a nitrogen derivative of carbonic acid of the general formula R ¹ R ¹ - NH- CN ■ r ³ in which X is an oxygen or sulfur atom or the imino group, R ^{1 is} a hydrogen atom, an alkyl group with less than 6 carbon atoms, an acyl group with less than 5 carbon atoms or a carbamyl group optionally substituted with alkyl groups with less than 4 carbon atoms, R ² for a hydrogen atom or an alkyl group with less than 6 carbon atoms and R ³ for a hydrogen atom, an alkyl group with less than 6 carbon atoms, an acyl group with less than 5 carbon atoms, a carbamyl group optionally substituted with alkyl groups with less than 4 carbon atoms or a saturated aliphatic ester group with less than 6 carbon atoms and b) an alcohol with 1 to 14 carbon atoms, which 2in optionally halogen-, alkyl-, alkoxy-, phenoxy- or amino-substituted aliphatic alcohol or an aromatic one Is alcohol or an optionally alkyl-substituted cycloaliphatic alcohol, where a molar ratio of alcohol to nitrogen derivative of carbonic acid of 0.1 to 2 complies with and the propellant mixture in an amount of? up to 100% by weight. based on the Vinyl chloride polymer is used. Substances and the decomposition products cause the polyvinyl chloride to foam. It is still known to use oxalic acid and urea as propellants and these mixed with polyvinyl chloride to heat. In these reactions, however, only a weak evolution of gas occurs, so that none Have foams made with a low density. Comparative tests have also shown that the combination of urea and oxalic acid becomes a very irregular and partially collapsed one Cell structure of the foam leads Sodium carbonate in the presence of an acid such as tartaric acid has also been used as a propellant It is also known. Polyvinyl chloride with the help of • 5 sodium borohydride to expand under the action an acid releases hydrogen which, however, is a flammable and, above all, diffusing gas Propellants also have in common that they can only be used with difficulty or with caution ίο react with each other already at room temperature, so that the expansion is difficult to control. Furthermore, urea oxalate, which decomposes under heat, has been tested as a propellant for polyvinyl chloride; but this connection must be established beforehand. In fact, when adding the above-mentioned mixture of oxalic acid and urea to polyvinyl chloride, different results are obtained than when adding urea oxalate previously prepared.
The aim of the invention is to avoid the disadvantages of the known processes for foaming polyvinyl chloride and to enable the production of cellular products with a lower density from vinyl chloride polymers by using a blowing agent system which is easy to use and whose decomposition products are not flammable and which can be applied to all known processing methods for polyvinyl chloride. The subject of the invention is a process for the production of foams based on vinyl chloride polymers using one a nitrogen derivative of carbonic acid and another organic one Compound containing propellant mixture, wherein the vinyl chloride polymer with the propellant and optionally mixed with plasticizers, stabilizers and other common additives, the mixture gels, is deformed and foamed, characterized in that a blowing agent mixture is used which a) a nitrogen derivative of carbonic acid of general formula R ² 2. The method according to claim 1, characterized in that the alcohol is mixed with up to 50 mol% of carboxylic acid is used.