CA2067128A1

CA2067128A1 - Pasty expandable composition based on vinyl chloride polymers, plasticizers and solid blowing agents and process for its preparation

Info

Publication number: CA2067128A1
Application number: CA002067128A
Authority: CA
Inventors: Emanuel Fakir
Original assignee: Robra-Chemie Brandenburger KG GmbH
Current assignee: Robra-Chemie Brandenburger KG GmbH
Priority date: 1989-09-25
Filing date: 1990-09-07
Publication date: 1991-03-26
Also published as: EP0494182B1; WO1991004289A1; EP0494182A1; DE59006530D1; DE3931917A1; DE3931917C2; ATE108811T1

Abstract

SUBSTITUTE
REMPLACEMENT
SECTION is not Present Cette Section est Absente

Description

2 ~ 2 ~
WO 91/04289 - 2 - PCT/EP90/015~4 Pasty expandable compositions of vinyl chloride polymers, in particular polyvinyl chloride, plasticizers and solid blowing agents are known. The foams obtained from them by heating and gelling the pastes and decomposing the blowing agents are, as a rule, designated as "flexible PVC foam". Such foams are used in various area~ of industry.

However, the known compositions and foams of this type still have various deficiencies. Thus, for exampl~, many ~'flexible PVC foams~ do not have satisfactory stability of the resulting foam elements and/or have too high a density. Other known flexible foams o this type require for their preparation starting materials which are too expensive and/or process steps which are too complicated.

British Patent 1,477,784 relates to a process for the -preparation of particularly flexible ~oam materials, in which a plastigel or plastisol of polyvinyl chloride or a vinyl chloride copolymer, a plasticizer and a blowing agent is expanded in a multistaga process while ;~
maintaining aertain temperature and pressure conditions.
This document, like the present invention, describes foams of PVC in combination with plasticizers based on phthalic esters. Nevertheless, a polymeric mixture is described there which contains essentially no fillers and also no nucleating agents~ both components which are essential for the present invention. This publication thu~ does not 9Ugge9t the subject of the present invantion.
; '~
The disadvantages of the known products gives rise to the desire for improved products which do not have these disadvantages and are suitable in particular for use in th~ area o~ insulating materials in the automotive industry and as foams in the building industry.It is therefore the object of the in~ention to provide an impro~ed pasty expandable composition based on vinyl ~;
chloride polymers, plasticizers and solid blowing agents, ':
` ~ ' ' , ~ 2 ~ ~ r~

- 3 - PCT/EP90/01~04 which does not have the disadvantages describPd and is suitable in particular for filling cavities. The object also includes the provision of processes for the preparation of such compositions and for their processing to foams.

~his object is achieved by a polymer composition which contain [sic], as essential components, a copolymer predominantly containing vinyl chloride, a plasticizer mixture, a solid blowing agent, a filler and a nucleating agent, and optionally at least one of the following component~: benzine, a stabilizer, a cell size regulator, a reinforcing fiber material or other ~onven-tional additives for this purpose, in each case in specific quantity ranges.
: , ., lS The present invention thus relates to a pasty expandable .:
compo~ition based on vinyl chloride polymers, plasticizer~ and solid blowing agents, which contain~ .
25 to 45 parts by weight of a copo:Lymer of a predominant amount of vinyl chloride and one or more olefinically unsaturated comonomer~ copolymerizable with vinyl chloride, 22 to 28 parts by weight of a pla~ticizer mixture ~ .:
containing dioctyl phthalate and diisobutyl phthalate, 18 to 30 parts by weight of a filler, 6 to 11 part~ by weight of a solid blowing agent which i9 decompo~able by heating with elimination of ga3, - 0.2 to 2.5 parts by weight of a nucleating agent, 0 to 5 parts by weight o~ benzine, 0 to 0.3 part by weight of a stabilizer, 0 to 5 part~ by weight of a cell size regulator, 0 to 15 parts by weight of a reinforcing fiber material and optionally up to 5 part~ by weight of other conven-tional additives for expandable polyvinyl chloride~
plasticizer plastisolst the total amount o~ all components being as a rule 100 parts by weight.~:

-~`` 2~71~

The copolymer contained in the composition according to the invention is present in the composition in an amount of 25 to 45 parts by weight, preferably 28 to 32 parts by weight, relative to the total weight of the composition, and contains, in polymerized form, a predominant amount, preferably at least 90 parts by weight, particularly preferably at least 94 parts by weight and in particular about 96 parts by weight, of vinyl chloride and correspondiny amounts, summing to 100% parts by weight [sic], of at least one olefinic comonomer which i5 copolymerizable with vinyl chloride. Preferred --comonomers are olefinic comonomer~ containing ester groups. Such comonomers are vinyl esters or esters of ~ -ole~inically unsaturated mono- or dicarboxylic acids, -such as acrylic acid, methacrylic acid, maleic acid, fumaric acid or itaconic acid. The esters of the olefinically unsaturated carboxylic acids contain, as alcoholic components, preferably saturated aliphatic alcohols having 1 to 4 C atoms. Among the vinyl esters, those of aliphatic saturated carboxylic acids having 1 to 4 car~on atoms are preferred. Examples of further suitable olefinic comonomer~ are ethylene, acrylonitrile and acrylamide. ;

The copolymers used for the preparation o~ the composi-tion according to the invention are advantageously in the form of fine-particled materials and are preferably obtained by emulsion polymerization. Their molecular weights and their particle sizes are of the same orders of magnitude a~ those of the polyvinyl chloride types usually u~ed for polyvinyl rhloride pa~tes. The plas-ticizer component of the composition according to the invention contains two or three phthalic esters. In the case of all plasticizer mixture~ which are suitable here, dioctyl phthalate, which i~ well known as a pla ticizer for polyvinyl chloride, is a component of the plasticizer mixture. In combination with this plasticizer, either dibutyl phthalate or diisobutyl phthalate i~ present a~
an additional plasticizer in the plasticizer mixture. In ';:, .'.
:.' ~- 2 ~ 2 ~

- 5 - PCT/EP90/01~04 a preferred embodiment of the invention, the plasticizer mixture contains, in addition to dioctyl phthalate, both dibutyl phthalate and diisobutyl phthalate. Preferred plasticizer mixtures are mixtures which contain 78 to 84 parts by weight, preferably 80 to 82 parts by weight, of dioctyl phthalate and 16 to 22 parts by weight, preferably 18 to 20 parts by weight, of dibutyl phthalate or diisobutyl phthalate. Another preferred plasticizer mixture contains 15 to 25 par~s by weight of dioctyl phthalate, 30 to 50 parts by weight of dibutyl phthalate and 30 to 50 parts by weight of diisobutyl phthalate.
Preferred embodiments of the mixtures of the plasticizers of three phthalic esters contain 18 to 22 parts by weight, preEerably 18 to 20 parts by weight, of dioctyl phthalate, 36 to 44 parts by weight of dibutyl phthalate and 36 to 44 parts by weight of diisobutyl phthalate and in particular 20 parts by weight of dioctyl phthalate, 40 parts ~y weight of dibutyl phthalate and 40 parts by weight of diisobutyl phthalate.

Instead of the mixture of the pla~ticizers, individual plasticizers in corresponding amounts, which then give the desired plastiaizer mixture during the preparation of the pa~te, can also be used in the preparation of the pastes.

Am~ng the solid blowing agents, organic blowing agents, in particular azodicarboxamide, a20bis(isobutyronitrile), diphenyl oxide, disulfonic hydrazide or organic N-nitro~o compounds, are suitable for the invention. The blowing agents are present in the pa~ty compoi3ition in an amount of 6 to 11 partR by weight, preferably 6 to 8 parts by weight.

Suitable filler~ are fillers known for the preparation of polyvinyl chloride pastes, calcium carbonate fillers beîng preferred. Untreated chalk is a parti~ularly suitable filler.

2 ~ ~ ~ 1 2 ~

- 6 - PCT/EP90/01~04 A further component of the composition according to the invention comprises solvent naphthas which account for an amount of 0 to 5 parts by weight, preferably 2 to 4 parts by weight, in particular 3 parts by weight, in the composition and as a rule have boiling limits of 109 to 335C, for example ~Corbasol" from the Cologne benzine refinery. -. - .
The nucleating agent i5 present in the composition in an amount of 0.2 to 2.5 parts by weight, preferably 0.2 to 1.2 parts by weight, very preferably 0.5 to 1 part by weight. A preferred nucleating agent is zinc oxide.
Examples of other suitable nucleating agents are silica aerogel, calcium stearate, cadmium-zinc and potassium-zinc ("Irgastab K 101" from Ciba-Geigy).

The stabilizer which i~ optionally used in the composi-tion according to the inventiorl has the object of maintaining the size and shape of the foam obtained by heating the pasty composition. As a rule, it i~ used in an amount of 0 to 0.3 part by weight, preferably 0.05 to 0.2 part by weight and in particu:Lar 0.1 part by weight of the composition. A cell size regulator, in particular sodium bicarbonate, may be used as a further component in the composition according to the :Lnvention. Its amount may be from 0 to 5 parts by weight, amounts of 2 to 4 2S parts by weight, in particular 3 parts by weight, being preferred.

A reinforcing fiber material may also be pre~ent as an optional component i~ the pasty composition according to the inventio~, in amount~ of 0 to 15 parts by weiqht, preferably 0 to 5 parts by weight. Such pastes are suitable in particular for the preparatîon of foams for the building industry. Examples of reinforcing fiber materials are glass fibers, rockwool and polyamide fibers.

The preparation of the pasty expandable compositions i~

, :- ~ .. , . .. , . . .. ' .', :: :'.

-- 2~7~

- 7 - PCT/EP90/015.04 effected by mixing the starting materials while avoiding gelling o~ the paste formed. For this purpose, mixing of the starting materials is preferably carried out at a temperature of 20 to 30C. As a rule, the plasticizer mixture is taken and the solid starting materials are stirred in. Conventional stirring or mixing apparatuses for the preparation of pastes may be usedO For produc-tion on a larger scale, apparatuses as used for the production of polyvinyl chloride pastes are suitable suitable are [sic], for example dissolvers, planetary stirrers or disk stirrers.

The pasty compositions according to the invention can be used for the production of foams having substantially closed cells. For this purpose, the pasty compositions are heated to a temperature at which gelling of the material occurs and decomposition of the blowing agent with elimination of gas kakes place. The heating temperatures are preferably 120 to 180C, and the heating temperature and the heating time are matched with one another so that maximum expansion of the paste is achieved. A~ a rule, a heating time of 20 to 35 minutes i9 required for this purpose.
, . ..
In an embodiment of the invention which i9 suitable in particular ~n the automotive industry for the production of insulating materials, the pasty ~ompo~ition i9 heated in a cavity and the amount of the composition and the volume o~ the cavity are matched with one another so tha~
the cavity is at lea3t substantially filled by the expanded composition.
The Examples which follow illustrate various embodiments of the invention. A11 data on amounts relate to weight in percent by weight but are stated below as absolute parts by weight (parts by weight), unless expressly ~tated otherwise. As a rule, the chosen ~mounts in parts by weight sum to 100 parts by weight.

. :

. . : : ' : -:

.

` 2~6'12~

Example 1 The following starting materials are introduced into a `
laboratory dissolver in the stated order at room temperature:
40 g of a plasticizer mixture of 80% of dioctyl phthalate and 20% of dibutyl phthalate, 3.5 g of a solvent naphtha having the boiling limits of 150 - 190C, 26 g of a copolymer predominantly containing vinyl -chloride (Vestolit B 7090 HUls AG, FRG), 25.5 g of untreated circles [sic]
(Juraperle BS from Ulmer Fullstoff-Vertriebs-&mbH) Sieve analysis 32-40 ~m; 2.7 g/cm3; bulk density 695 kg/m3, 8~8 g of azodicarboxamide, 2.5 g of zinc oxide, O.1 g of dicyanodiamide and 10 g of polyamide fiber (fiber length of about 10 ~m). ' ~he copolymer is introduced into the initially taken mixture of plasticizer and benzine at a stirrer ~peed of 300 rpm, and the mixture obtained is stirred for 20 minutes. Thereafter, the chalk i~ slowly added in the course of 2 minutes and the mixture i9 then ~tirred for a further 3 minute~, the stirring speed being increased to 500 rpm. This is followed by the addition of the other ~tarting materials and the prepared mixture is ~tirred for about 10 minutes at B50 rpm~ it being ensured `;-that its temperature doeR not exceed 32C.

The pasty expandable composition obtained has a long shelf life at 20C or lower temperatures. ~`
~ .
Similar composition~ are obtain~d if, instead of the specific starting materials mentioned, other sub tances stated in the description are used, ~or example rockwool, glass fibers or polyacrylonitrile fibers instead of polyamide fibers.

, ,. . ~,, ~ : .

--" 2~67L2~

- 9 - PC~/EP90/015.04 Example 2 .:
The composition which can be prepared according to Example 1 can be sprayed in a spray gun having a nozzle of 0 . 8 mm at a pressure of 5 bar and at 22 C and can be gelled and expanded by heating to about 160C. For example, a gelling apparatus from Xorper-Schmidt can be used for this gelling.

An advantageous gelling time is 20 minutes.

After the gelling and expansion, the material forms a fine-pore foam having su~stantially closed cells, which retains its height of rise during storage and use and whose density, in the case of the composition of the starting materials stated in Example 1, is 1.45 g/cm3 .

: . , - . . . .....

. .

Claims

Patent Claims

1. A pasty expandable composition based on vinyl chloride polymers, plasticizers and solid blowing agents, which contains 25 to 45 parts by weight of a copolymer of a predominant amount of vinyl chloride and one or more olefinically unsaturated comonomers which are copolymerizable with vinyl chloride, 22 to 28 parts by weight of a plasticizer mixture containing dioctyl phthalate and at least one of the plasticizers dibutyl phthalate and diisobutyl phthalate, 18 to 30 parts by weight of a filler, 6 to 11 parts by weight of a solid blowing agent which can be decomposed by heating with elimination of gas, 0.2 - 2.5 parts by weight of a nucleating agent, 0 to 5 parts by weight of benzine, 0 to 0.3 parts by weight of a stabilizer, 0 to 5 parts by weight of a cell size regulator, 0 to 15 parts by weight of a reinforcing fiber material and optionally up to 5 parts by weight of other conventional additives for expandable polyvinyl chloride/plasticizer plastisols.

2. A composition as claimed in claim 1, wherein the comonomer of the copolymer is a comonomer containing ester groups.

3. A composition as claimed in claim 1 or 2, wherein the copolymer is a copolymer which contains at least 90 parts by weight of vinyl chloride and, as a comonomer, a vinyl ester of an aliphatic saturated monocarboxylic acid having 1 to 4 carbon atoms in the molecule.

4. A composition as claimed in any of claims 1 to 3, wherein the copolymer contains at least 94 parts by weight of vinyl chloride and 2 to 6 parts by weight of the comonomer.

5. A composition as claimed in any of claims 1 to 4, wherein the copolymer contains about 96 parts by weight of vinyl chloride and about 4 parts by weight of comonomer.

6. A composition as claimed in claim 5, wherein the comonomer is vinyl acetate.

7. A composition as claimed in any of claims 1 to 6, wherein the plasticizer mixture contains 78 to 84 parts by weight of dioctyl phthalate and 16 to 22 parts by weight of dibutyl phthalate or diisobutyl phthalate.

8. A composition as claimed in any of claims 1 to 6, wherein the plasticizer mixture contains 15 to 25 parts by weight of dioctyl phthalate, 30 to 50 parts by weight of dibutyl phthalate and 30 to 50 parts by weight of dibutyl phthalate [sic] and 30 to 50 parts by weight of diiso-butyl phthalate, these parts by weight being relative to the plasticizer mixture.

9. A composition as claimed in claim 8, wherein the plasticizer mixture contains 18 to 22 parts by weight of dioctyl phthalate, 36 to 44 parts by weight of dibutyl phthalate and 36 to 44 parts by weight of diisobutyl phthalate.

10. A composition as claimed in claim 9, wherein the plasticizer mixture contains 20 parts by weight of dioctyl phthalate, 40 parts by weight of dibutyl phthalate and 40 parts by weight of diisobutyl phthalate.

11. A composition as claimed in any of claims 1 to 10, wherein the blowing agent is an organic blowing agent.

12. A composition as claimed in claim 11, wherein the blowing agent is at least one of the blowing agents azodicarboxamide, azobis-(isobutyronitrile), diphenyl oxide, disulfonic hydrazide or an organic N-nitroso compound.

13. A composition as claimed in any of claims 1 to 12, wherein the filler is calcium carbonate.

14. A composition as claimed in claim 13, wherein the filler is untreated chalk.

15. A composition as claimed in any of claims 1 to 14, wherein the nucleating agent is zinc oxide.

16. A composition as claimed in any of claims 1 to 15, wherein the benzine is a solvent naphtha.

17. A composition as claimed in any of claims 1 to 16, wherein the stabilizer is dicyanodiamide.

18. A composition as claimed in any of claims 1 to 17, wherein the cell size regulator is sodium bicarbonate.

19. A process for the preparation of a composition as claimed in any of claims 1 to 18, wherein the stated starting materials are mixed while avoiding gelling.

20. A process as claimed in claim 19, wherein mixing of the starting materials is carried out at a temperature of 20 to 30°C.

21. A process for the preparation of a foam from one of the compositions as claimed in any of claims 1 to 18, wherein the mixed pasty starting materials are heated to a temperature at which gelling of the material and decom-position of the blowing agent occur.

22. A process as claimed in claim 21, wherein the composition is heated to a temperature of 120 to 180°C.

23. A process as claimed in either of claims 21 or 22, wherein the heating temperature and the heating time are such that maximum expansion of the material is achieved.

24. A process as claimed in any of claims 21 to 23, wherein heating of the pasty composition is carried out in a cavity and the amount of the composition and the volume of the cavity are matched with one another so that the cavity is at least substantially filled by the expanded composition.