DE2018527C3 - Process for the production of foams based on vinyl chloride polymers - Google Patents

Description

R ²

_R i_ _NH _ _c _ _N

55

The present application relates to an addition to main patent 20 18 532 »Method for Manufacture of foams based on vinyl chloride polymers «, according to which soft or rigid Foams based on polyvinyl chloride can be obtained with the help of a novel blowing agent.

It is generally known to add organic substances, such as biuret, to polyvinyl chloride for the production of foams and then to heat the mixture. The organic substances decompose and the decomposition products cause the polyvinyl chloride to foam. It is also where X is an oxygen or sulfur atom or the imino group, R ^{1 is} a hydrogen atom, an alkyl group with fewer than 6 carbon atoms, an acyl group with fewer than 5 carbon atoms or a carbamyl group optionally substituted with alkyl groups with fewer than 4 carbon atoms R ² denotes a hydrogen atom or an alkyl group with fewer than 6 carbon atoms and R ³ denotes a hydrogen atom, an alkyl group with fewer than 6 carbon atoms, an acyl group with fewer than 5 carbon atoms, a carbamyl group optionally substituted with alkyl groups with fewer than 4 carbon atoms or a saturated one aliphatic

Is ester group having fewer than 6 carbon atoms, optionally having 3 to 12 carbon atoms substituted unsaturated aliphatic or optionally substituted aromatic monocarboxylic acid, Dicarboxylic acid or its anhydrides used and a molar ratio of unsaturated acid to nitrogen derivative of carbonic acid of 0.2 to 2 is maintained and that Propellant mixture is used in an amount of 2 to 100% by weight, based on the vinyl chloride polymer is according to patent application P 2018 532.4-43, ι ο characterized in that the organic acid used is at least one having 3 to 18 carbon atoms saturated optionally cyano, chlorine, bromine, alkyl, aryl, aryloxy or chloroaryloxy substituted aliphatic Carboxylic acid and / or a corresponding anhydride is used

Vinyl chloride polymers in the context of the description are the homo- and copolymers as well as post-chlorinated ones Polymers of vinyl chloride, their mixtures with each other or with other compatible polymers, such as Polypropylene, polyethylene, polystyrene, polyurethane, vinyl acetate-ethylene copolymers and acrylonitrile-butadiene-styrene copolymers.

If a mixture of vinyl chloride polymer and other compatible polymers is used, the The proportion of vinyl chloride polymer is 50 to 99% by weight of the total mixture. The vinyl chloride polymer should consist of at least 50% by weight of vinyl chloride units; as comonomers come vinyl esters, such as

Vinyl acetate, alkyl acrylates and alkyl methacrylates, fumaric acid esters, maleic acid esters,
Chiort'umaric acid ester, chloromaleic acid ester,
Alkyl vinyl ether, vinylidene chloride, vinyl pyridine,
Ethylene, propylene, acrylonitrile and vinyl alcohol
in question. The copolymer can also be a vinyl chloride mono- or copolymer, which with butadiene and acrylonitrile with butadiene and an alkyl methacrylate and / or alkyl acrylate, with butadiene, a. Alkyl acrylate, styrene and a crosslinking agent such as divinylbenzene is grafted.

The polymers are known in any known manner by bulk polymerization, suspension polymerization, Polymerization in fine suspension or microsuspension or by emulsion polymerization manufactured.

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

As examples of the nitrogen derivatives of carbonic acid that correspond to the formula given, mainly urea, biuret, thiourea, acetylurea, diacetylurea, triuret, guanidine, lower alkyl allophanates, lower alkyl carbamyl allophanates, N-methyl-N'-acetylurea and N-methyl- "55 Called Ν ', Ν'-dimethylurea.

The optionally substituted saturated aliphatic acids used according to the invention and the saturated cycloaliphatic acids - the other component of the propellant according to the invention - are the monocarboxylic acids and dicarboxylic acids with 3 to 18 carbon atoms, preferably with 3 to 8 Carbon atoms and the corresponding acid anhydrides.

Examples are the monocarboxylic acids corresponding to this definition

Propionic acid, butyric acid, valeric acid,
Caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, 2-cyanobutyric acid, 2-chlorocaproic acid, 2-ethylcaproic acid, phenylacetic acid, phenylmethylacetic acid, phenoxyacetic acid, dichlorophenoxyacetic acid,
Cyelopropanecarboxylic acid, Cyclobutanecarboxylic acid and Cyclopentanecarboxylic acid

named The dicarboxylic acids include, for example

Malonic acid, succinic acid,
Glutaric acid, adipic acid, sebacic acid, decanedicarboxylic acid (CH ₂ ), o · (COOH) ₂ and cyclopentanedicarboxylic acid.

Examples of anhydrides are mainly succinic anhydride and propionic anhydride.

The molar ratio of saturated aliphatic acid or cycloaliphatic acid maintained according to the invention Acid to nitrogen derivative of carbonic acid is preferably 0.4 to 1.5.

There are at least one of said saturated acids with at least one nitrogen derivative of the Carbon dioxide combined to form a propellant mixture, the decomposition temperature of which is at least equal to Gel temperature of the vinyl chloride polymer is or above. Preferably, the blowing agent mixture added to the vinyl chloride polymer in an amount of 2 to 40% by weight, based on the polymer

Depending on whether a rigid or more or less flexible or soft cellular product is sought is the vinyl chloride polymer with varying amounts of one or more plasticizers offset as they are usually used in the processing of vinyl chloride polymers. this are especially

Butyl benzyl phthalate, dioctyl phthalate, dibutyl phthalate, dicapryl phthalate, Dinonyl phthalate; Dioctyl adipate, didecyl adipate; Dibutyl sebacate dioctyl sebacate; Tricresyl phosphate Trioctyl phosphate.trixylyl phosphate octyl diphenyl phosphate; chlorinated paraffins; epoxidized oils and esters; polymeric plasticizers such as adipic acid or polyester of sebacic acid and plasticizers that are solid at room temperature, such as polymethylacrylates and polymethyl methacrylate, polyethyl acrylate and polyethyl methacrylate, polybutyl acrylate and Polybutyl methacrylate and the fatty alcohols. The plasticizers are the vinyl chloride polymers added in amounts of 0 to 150% by weight, depending on the desired degree of softness of the cellular product or foam.

Crosslinkable plasticizers can be used, such as diallyl phthalate, ethylene glycol mono- or -dimethacrylate propylene glycol mono- or dimethacrylate, unsaturated polyester, with which after the Crosslinking foams with noticeably improved dimensional stability in the heat can be obtained.

The crosslinkable plasticizers are used in amounts of 0 to 25% by weight, based on the vinyl chloride polymer, used.

In addition to the plasticizers, the vinyl chloride polymers can be mixed with conventional stabilizers and Lubricants are added.

The neutral or basic lead salts are mentioned as stabilizers: carbonate, sulfate, phosphite, Silicate and stearate; the salts of calcium, cadmium, barium, zinc, lithium and strontium, especially those Stearates, octoates and laurates; the tin compounds:

Diaurate and dimaleinate of dibutyltin and dioctyltin and mercapto compounds such as thioctyltin and thiobutyltin; Zinc oxide and / or urea and / or biuret (French patent 14 75 865). The stabilizers are added in amounts from G2 to 8% by weight, based on the vinyl chloride polymer.

The nature and amount of lubricants added depends on the processing method chosen away. Stearic acid, neutral oiler basic lead tarates, ethyl palmitate, paraffin waxes, Ester waxes, which are added in amounts of 0.1 to 3% by weight, based on the vinyl chloride polymer.

In some cases it is advantageous to include other customary auxiliaries in the vinyl chloride polymers to incorporate; these are, for example, fillers, nucleating agents, structure regulators, crosslinking agents and Dyes (pigments).

Fillers such as chalk, kaolin, silica, soot 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 azo compound, such as azodicarbonamide, isopropyl azoformate, barium azodicarboxylate or RuS; their amount should be 0.05 to 1.5% by weight of the vinyl chloride polymer.

The main structural regulators are condensation products from ethylene oxide and fatty acids and analogous products in question, which are used in amounts of 0.05 to 1% by weight, based on the vinyl chloride polymer will.

All crosslinkable substances with vinyl chloride polymers come into consideration as crosslinking agents are compatible, for example an ethylene-vinyl acetate copolymer, a polyvinyl chloride grafted with butadiene and acrylonitrile and the above-mentioned crosslinkable Plasticizers. These crosslinking agents are used in amounts from 0 to 25 percent by weight of the vinyl chloride polymer used The crosslinking takes place chemically in any known manner; she can can also be effected by irradiation.

The different components are mixed together and gelled using the usual processing methods, such as compression molding, injection molding, extrusion, calendering, coating, deformed and foamed; the various process steps can be carried out separately from one another or are combined with each other, for example gelling and foaming, gelling and deforming or combined shaping and foaming.

The blowing agent mixture to be used according to the invention can be used according to the vinyl chloride polymer Gelling can be added.

. When processing by compression molding, emulsion polymerization or Polymerization of vinyl chloride polymer produced in microsuspension is used. After mixing a paste is obtained which is then shaped and pressed under temperature and time conditions which lead to gelling. After cooling and demolding, the molding obtained is either heated with hot air or with steam or in a hot water or oil bath or by IR radiation, high frequency or Ultra high frequency is expanding.

For processing by extrusion, injection molding and calendering, a vinyl chloride polymer is used, which was produced by polymerization in bulk, in suspension, in microsuspension or in emulsion. The viscosity number of this polymer can be high if a soft foam is desired; sir. must be small if a rigid foam is to be produced.

During extrusion, the mixture is fed into an extruder and the extruded profile then expanded as indicated

ίο 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 are mixed with one another, gelled and deformed, then become Sheets or sheets drawn and also foamed as indicated

If the processing is carried out by coating or brushing with a plastisol, a Emulsion polymerisation or polymerisation in microsuspension produced vinyl chloride polymer is used All components are mixed together to form a paste. The gelation and expansion takes place when passing through the coating machine. It can also be coated with powdered mixtures but in this case a suspension or bulk polymerization is used 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 Foaming conditions. The diameter of the cells and their wall thickness depend on them Parameters.

With the aid of the propellant mixture according to the invention, numerous, very different Manufacture foam products, for example:

thin (<5 mm) flexible foams with a high density (> 0.2 g / cm ³ ),

thick (5 to 100 mm) flexible foams with a low density (<0.2 g / cm ³ ),
thick (5 to 100 mm) rigid foams in the entire possible range for volume weights (0.025 to 0.85 g / cm ³ ).

The foams produced according to the invention and based on vinyl chloride polymers are diverse Application: for heat and sound insulation, as connecting parts, artificial leather, underlays for floor coverings, for upholstery, in construction, in furniture manufacture and as packaging materials.

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

example 1

A plastisol mixer was used at room temperature 200 g of polyvinyl chloride, produced by emulsion polymerization, viscosity number 180, determined according to the French standard T 51-013, 32.4 g urea, 38.8 g Adipic acid and 2 g zinc oxide charged and mixed for 15 minutes; thereupon was 70 g of butyl benzyl phthalate added and mixed for a further 10 min. A viscous paste was obtained with the consistency of Kittes.

This paste was placed in a cylindrical mold with an inner diameter of 7 cm and a height of 1 cm then at 180 ° C under a pressure of 100 Rar

pressed for 50 min. It was then cooled to room temperature and under the same pressure for 20 minutes held.

The molding was removed from the mold and left to rest for 20 minutes before being placed in an oven at 120 ° C. for 15 minutes min was foamed.

A somewhat soft, cellular product with a density of 0.09 g / cm ^{3 was obtained} .

Example 2 to 4

The procedure was as in Example 1, but the 38.8 g of adipic acid were replaced by various dicarboxylic acids replaced in the corresponding amount.

The conditions and the test results are summarized in Table 1 below.

Table 1

at Dicarboxylic acids crowd Foams Be games Art space create Weight Ness g / cm ³

2 Malonic acid 27.6 0.14 soft 3 Succinic acid 31 0.17 soft 4th Decanedioic acid 68 0.40 something soft

Example 5

The procedure was as in Example 1, except that 39 g of propionic acid were used instead of 38.8 g of adipic acid. A somewhat flexible foam with a density of 0.24 g / cm ^{3 was obtained} .

Example 6

Example 1 was repeated with 26.2 g of succinic anhydride instead of 38.8 g of adipic acid. A flexible foam with a density of 0.1 g / cm ^{3 was obtained} .

Example 7 and 8

The procedure was as in Example 1, with the modification that other than urea Nitrogen derivatives of carbonic acid were used.

The individual conditions and the results are summarized in Table 2 below.

Table 2

The mixture was kneaded in a roller mixer at 115 ° C. for 10 minutes until it gelled. It was < further kneaded and added a mixture of 160 g of urea and 200 g of adipic acid. Then nocl kneaded for a further 10 min.

The mass was drawn out into films which were allowed to cool on a flat surface. Then di "films were foamed at 200 ⁰ C for 15 min.

A rigid foam with a density of 0.1 g / cm ³ was obtained.

Example 10
A mixture was made from:

500 g polyvinyl chloride, produced by bulk polymerization, viscosity number 60 (French Standard T 51-013),

500 g copolymer of vinyl chloride and vinyl acetate containing 15% vinyl acetate units, produced by suspension polymerization, viscosity number 60,
162 g urea,
194 g adipic acid,
50 g dioctyl phthalate,
30 g dibasic lead stearate and
10 g dibasic lead phosphite.

The mixture was on a for 10 minutes

Roller mixer kneaded at 110 ⁰ C until gelling.

Films were then drawn out and allowed to cool on a flat surface. The foils were then foamed in the oven at 180 ^° C. for 15 minutes

The product obtained was a rigid foam with a density of 0.25 g / cm ³ .
35

At- nitrogen derivative of carbonic acid

Kind of amount

Foam

Volume weight fenheit g / cm ³

7th . Biuret 32.4 0.04 soft

8 acetylurea 54.4 0.12 soft

Example 9 A mixture was prepared from:

tOOÖg copolymer of vinyl chloride and vinyl acetate, containing 15% vinyl acetate units, produced by suspension polymerization, with ifrihNTSl ^ ia)

30 g tribasBches sample, 3g foasic lead stearate

Example 11
The following were mixed together:

1000 g copolymer of vinyl chloride and vinyl acetate, containing 15% vinyl acetate units, produced by suspension polymerization, viscosity number 60 (French standard T51-013),
160 g urea,
200 g adipic acid,

50 g ethylene glycol methacrylate,

1 g cumene hydroperoxide,
30 g tribasic lead sulfate and
3 g dibasic lead stearate
50

The mixture was in a roller mixer for 10 min

Kneaded at 00 ° C until the skin was turned. A film was then drawn and allowed to cool on a flat surface . The sheet was foamed in an oven at 200 ⁰ C for 15 minutes and crosslinked

The finished product was a rigid foam with a density in the range of 0.1 g / cm ³ .

The dimensional stability under heat was measured with a test specimen 40 mm × 40 mm × 20 ram under a load of 250 g / cm ² , the temperature at which the thickness of the test specimen had decreased by 5% was determined. This temperature was 85 ° C

An experiment with the same was used for comparison Formulation, but without acetylene glycol mealyerylate and

carried out without cumene hydroperoxide

Rigid foam with a density of 0.1 g / at ^{3 had} a Warm shape stable by me 75 ° C ami

709610/150

'/ 901

lö b'll

10

Example 12

In a plastisol mixer were at room temperature mixed together:

600 g of polyvinyl chloride, obtained by emulsion polymerization, with a viscosity number of 180 (French Standard T 51-013),

12 g urea, ι ο

15 g adipic acid and
9 g mixture of cadmium octoate and zinc octoate.

After mixing for 10 minutes, 400 g of butyl benzyl phthalate was added and an additional 30 minutes mixed.

The paste obtained was crushed, degassed and then spread on a fabric. The coated fabric was passed through a tunnel oven at 200 ^° C. for 3 minutes; the finished product was a flexible foam, density 0.55 g / cm ³ , coated fabric.

Comparative experiments

Comparative tests were carried out against the stanc of the technology according to DT-PS 8 51 848 unc d: e Effect of the known propellant mixtures on oxalic acid and urea or a urea oxala with the effect of the propellant combination according to the invention in the production of PVC foam fen compared.

Comparative experiment 1

The general procedure of Examples 1 to 6 of the application was repeated with the modification that instead of the various acids or acid anhydrides used according to the invention, the equimo lare amount, i.e. 23.6 g of oxalic acid were used. It became a semi-rigid foam with see: irregular and partially collapsed cell structure.

The results are given in the table below, the results mentioned in the examples of the application juxtaposed.

Examples acid Foam structure g / cm ³ nature very irregular, partly Comparison 1 Oxalic acid 0.6 semi-rigid collapsed regularly, not together 1 Adipic acid 0.09 somewhat soft please the same 2 Malonic acid 0.14 soft the same 3 Succinic acid 0.17 soft the same 4th Decanedicarboxylic acid 0.40 somewhat soft the same 5 Propionic acid 0.24 soft the same 6th Succinic anhydride 0.1 soft irregular and collapsed: and coarser, Comparative experiment 2 40 cell structure.

Example 9 of the application was repeated with 118 g of oxalic acid instead of 200 g of adipic acid. the The mass was difficult to knead and stuck to the apparatus in places; also sat down large amounts of crusts on the cylinders of the kneading machine.

A foam with a density of 0.4 g / cm ^{3 was obtained.} In contrast to this, the foam mixture could be formed! Example 9 of the application knead without any difficulties and process into films; the mass did not stick in places, nor did it form crusts on the cylinders of the kneading machine. When foaming, a rigid foam with a density of 0.1 g / cm ³ and a fine, regular and non-collapsed structure was obtained.

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Claims (1)

Claim: Further development of the process for the production of foams on the basis of Vinyl chloride polymer using a nitrogen derivative of carbonic acid and an organic one Acid-containing propellant mixture; wherein the vinyl chloride polymer with the blowing agent and optionally mixed with plasticizers, stabilizers and other customary additives, the Mixture is gelled, shaped and foamed, the nitrogen derivative of carbonic acid of the formula R ² • 5 R ¹ -NH-C-N 4th
\ R ³ corresponds, in which X is an oxygen or sulfur atom or the imino group, R ^{1 is} a hydrogen atom, an alkyl group with fewer than 6 carbon atoms, an acyl group with fewer than 5 carbon atoms or a carbamyl group optionally substituted with alkyl groups with fewer than 4 carbon atoms, R ^{2 is} a Hydrogen atom or an alkyl group with fewer than 6 carbon atoms and R ³ a hydrogen atom, an alkyl group with fewer than 6 carbon atoms, an acyl group with fewer than 5 carbon atoms, a carbamyl group optionally substituted with alkyl groups with fewer than 4 carbon atoms or a saturated aliphatic ester group with less than 6 carbon atoms and an optionally substituted unsaturated aliphatic or optionally substituted aromatic monocarboxylic acid, dicarboxylic acid or their anhydrides having 3 to 12 carbon atoms and a molar ratio of unsaturated acid adhered to nitrogen derivative of carbonic acid from 0.2 to 2 and the propellant mixture in an amount of 2 to 100 wt .-%, based on the vinyl chloride polymer, is used according to main patent 20 18 532, characterized in that the organic acid at least one saturated, optionally cyano-, chloro-, bromo-, alkyl-, aryl-, aryloxy- or chloroaryloxy-substituted aliphatic carboxylic acid and / or a corresponding anhydride having 3 to 18 carbon atoms. known as blowing agents oxalic acid and urea too and to heat them mixed with polyvinyl chloride a In all of these reactions, however, only a weak evolution of gas occurs, so that none Have foams made with a low density. In addition, comparative tests have 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 to expand polyvinyl chloride with the aid of sodium borohydride, which releases hydrogen under the action of an acid, but which is a flammable and, above all, diffusing gas They also have in common that they can only be used with difficulty or with caution and react with one another even at room temperature, so that the expansion can only be controlled with difficulty. Furthermore, urea oxalate, which decomposes with heat, has been proposed as a blowing agent for polyvinyl chloride, but this connection must be made 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 invention aims to overcome the disadvantages of the known processes for foaming polyvinyl chloride to avoid and the production of foams with low density from vinyl chloride polymers to enable, by using a propellant system that is easily can be used whose decomposition products are not flammable and which applies to all known Can apply processing methods for polyvinyl chloride The subject of the invention is a further development of the method for producing foams the base of vinyl chloride polymers using a nitrogen derivative of carbonic acid and an organic acid-containing blowing agent mixture, wherein the vinyl chloride polymer with the Propellants and optionally plasticizers, stabilizers and other customary additives mixed, the Mixture is gelled, shaped and foamed, the nitrogen derivative of carbonic acid of the formula