EP0365577A1

EP0365577A1 - Process for stabilizing mixtures based on halogenated polymers

Info

Publication number: EP0365577A1
Application number: EP19880905881
Authority: EP
Inventors: Simon Kornbaum
Original assignee: Individual
Current assignee: KORNBAUM Simon
Priority date: 1987-06-26
Filing date: 1988-06-22
Publication date: 1990-05-02
Also published as: EP0299882A1; RO105578B1; BR8807588A; ES2040885T3; IL88604A; AU1966888A; HU205962B; ZA889283B; CN1043723A; WO1988010282A1; EP0299882B1; DE3880033D1; FR2617175B1; KR890701674A; JPH02504038A; FR2617175A1; US5166241A; CA1335012C; AU625411B2; ATE87952T1

Abstract

PCT No. PCT/FR88/00332 Sec. 371 Date Nov. 22, 1989 Sec. 102(e) Date Nov. 22, 1989 PCT Filed Jun. 22, 1988 PCT Pub. No. WO88/10282 PCT Pub. Date Dec. 29, 1988.Thiol compounds are combined with an organometallic halide or metallic halide to provide thermal stability to vinyl halide polymers.

Description

A method of stabilizing mixtures ^{• •} based on halogenated polymers.

The present invention relates to a process for stabilizing blends based on halogenated polymers or copolymers during their transformation, as well as the stabilization systems provided for this purpose. The method of the invention involves compositions stabili¬ cient for the protection of polymers and copolymers of halogen-containing and, in particular, polymers and copolymers of vinyl chloride (PVC), against ^the adverse effects of es heat, during their passage through processing machines such as calenders, extruders, kneaders, injection and coating machines and gelification tunnels. This process ensures the desired initial color and maintains color stability and thermal stability for sufficiently long periods of time.

It is known that polymers and copolymers containing halogens require, in order to be able to be transformed using heat, the addition of chemical compounds, commonly called thermal stabilizers, whose role is fourfold: a) to ensure at the start the desired color or the absence of coloring, b) maintaining the initial color of the molten material, without annoying change, for a sufficient duration; c) prevent thermal degradation of the molten material for a sufficiently long period and, d) in the case of finished products which must be transparent, not to compromise the intrinsic transparency of the polymer.

During processing, the temperature of the melt is, in the case of PVC, between 160 ° C and 230 ° C, depending on different factors: nature of PVC (plasticized ^'or rigid), K-value of PVC and finally the shear speed which the molten material undergoes in the machine. In general, the temperature is, for plasticized PVC, between 160 ° C and 190 ° C and for rigid PVC, between 200 ° C and 230 ° C.

The duration of the color stability and that of the thermal stability are, for a given mixture, inversely proportional to the temperature of the melt. Each time the temperature increases by 10 ° C, these times decrease by about half. This means, for example, that a system of thermal stabilizers which is satisfactory for the transformation of a mixture of PVC plasticized at 180 ° C, may be totally unsuitable for the transformation of rigid PVC at 220 ° C.

These technological particularities and considerations of the cost of stabilization explain the very wide variety of thermal stabilizers offered by producers, in order to satisfy the very large and very varied market for the transformation of PVC.

The use of organic compounds containing -SH functions, as PVC stabilizers in combination with other known thermal stabilizers, has been proposed. This is how they are used, for example:

- in combination with salts of Ba, Sr, Ca, Cd, Zn, Pb, Sn, Mg, Co, Al, Ni, Ti, phenols, aromatic carboxylic acids, fatty acids, epoxidized fatty acids (US- A-31 422);

- in combination with dialkylated tin carboxylates (US-A-3 063963);

- in combination with organotin oxides or with organo-antimony oxides (DE-C-1 217609).

Finally, US-A-3,715,333 mentions the association of organotin trichloride with a thioorganotinet of general formula R_ Sn (SR ') - ,. However, a privileged place goes to stabilizers of the thio-organotin type and in particular to those which correspond to the following formula:

^R l or 2 ⁵ⁿ (SCH ₂ COOC _s H ₁₇ ) 3 _{Qu 2}

or R = methyl, butyl or octyl.

At present, this type of stabilizer is the only one to satisfy, in the best condition of simplicity, the quadruple role mentioned above, in the case of transformation of rigid PVC at temperatures ranging from 200 ° C to 230 ° C . These stabilizers are used, almost exclusively, for the transformation of PVC into transparent rigid sheets and films, into hollow bodies - except bottles for mineral water, for organo-leptic reasons - and into rigid tubes in the United States and Japan and partly also in Europe, replacing lead stabilizers. The main disadvantages of these stabilizers are the complexity of their manufacture, the high rate of tin, from 1 to 20% and the high price. The object of the present invention is to provide thermal stabilizer compositions capable of fulfilling the performance of stabilizers of the thio-organotin type in the transformation of rigid PVCs while having significant advantages: simplicity of manufacture, reduction of the quantity of metal to around 1% and very significant reduction in the cost of stabilization.

The inventor has surprisingly discovered that the addition, to a mixture of rigid PVC containing one or more -SH functions (thiol compound), of a very small amount of a metallic or organometallic halide had the effect of 'remarkably improve the initial color, to extend both the duration of color stability and the duration of thermal stability. These results are all the more surprising since certain metal halides are known for their harmful effect on the thermal stability of PVC. The inventor has been able to determine that, in the case of organometallic halides, the improvements manifest themselves progressively up to a certain amount of addition, then, that, when the amount added is increased, there is a reduction in the duration color stability and thermal stability.

These findings lead to the concept - new in the field of PVC stabilization - of the contrasting action of certain metal halides in the presence of thiol compounds, which, depending on the quantity added, can promote or disadvantage color stability and thermal stability PVC.

Furthermore, metal halides - without organic radicals - added in very small quantities to PVC mixtures containing thiol compound, produce effects similar to the additions of organometallic halide; however, the intensity of these effects depends on the level of acidity of the metal halide.

The process for stabilizing halo-vinyl resins according to the invention is characterized in that it consists in adding, to the polymer to be protected, a system consisting of at least one organic compound containing one or more -SH- functions and a very small amount of at least one halide chosen from metallic and organometallic halides.

The halogenated resins to which the invention applies are the homopolymers and / or copolymers of vinyl chloride, of vinylidene chloride, of chlorofluoroethylene with the following comonomers: vinyl acetate, acrylonitrile, maleic anhydride, ethylene, propylene and other monomer copolymerizable with vinyl halides, as well as halogenated polyolefins and other halogenated polymers and elastomers, natural or synthetic.

The thiol compounds used in the process according to the invention have the following general formula:

R (R '-SH x) y (I)

in which: - R is the remainder of a monohydroxyl alcohol of any chemical nature such as: aliphatic, olefinic, cyclic, heterocyclic, aromatic, or the rest _. of a monomeric polyol such as: glycerol, glycoi, pentaerythritis, sorbitol, pentites, hexites, monosaccharides, or the rest of a polymeric polyol such as polyethylene glycol, polypropylene glycol, polyvinyl alcohol, cellulose, starch and other polysaccharides , R being able to carry various functions such as etheroxide, -carboxylic ester -thiocarbonic, -sulfonic or / and ester of other anorganic acids.

- R '-SH is the remainder of a monoacid or of a polycarboxylic acid, containing one or more -SH functions, linked to R by esterification, such as, for example, -thioglycolic acid, -mercaptopropionic acid, -mercaptosuccinique, -dimercaptosuccinique, -thiosalicyiique.

- x is the number of -SH linked to R '.

- y ^} is the number of R'-SH x linked to R.

The added amount of organic compound containing one or more -SH function (s) is between 0.1 and 5 parts by weight per 100 parts by weight of resin and preferably between 0.3 and 1.5 parts by weight per 100 parts by weight of resin.

The organometallic halides used in the process according to the invention have the following general formula:

R Me (v) n Hal v-n (II)

in which :

- R is an aliphatic, cyclic, heterocyclic, aromatic organic residue, containing or not containing radicals and / or simple or mixed functions.

- n is the number of R linked to the metal Me. - Me = Sn, Al, B, Sb, Fe, Cd, Zn, Ti, Hg, Bi, Mn or Ga.

- v is the valence of Me.

- Hal - chlorine, bromine, iodine, fluorine.

^" The metal halides preferred in the process according to the invention have the following general formula:

Me (v) Hal. (III)

V

in which :

- Me is a metal of which the halogen salt gives, in aqueous solution of approximately 35 meq. of halogen per liter of distilled water at around 23 ° C, a pH equal to or less than 5, preferably a pH equal to or less than 3.

- v is the valence of Me. - Hal = chlorine, bromine, iodine, fluorine.

One can use an organometallic halide or a metallic halide of a single chemical species or else a mixture of at least one organometallic halide and / or at least one metallic halide. Due to the very small amount required, it is desirable that the halide is easily metered and dispersed homogeneously in the PVC mixture. For this reason, it is recommended to dilute the halide in a suitable solvent or medium, such as in one or more components of the mixture.

In the present description, the term mixture corresponds to the material intended for processing, obtained by homogenization of several components and the basic component of which is one or more polymers or / and halogenated copolymers and comprising, in addition to the adjuvants I, II or / and III described above, one or more other components such as: anti-shock additives, processing aids, known PVC stabilizers, plasticizers, fillers, dyes, anti-static agents and any usual adjuvant.

The present invention will be better understood and its advantages will emerge clearly from the following examples which illustrate it without limiting it. PVC mixtures, the components of which are specified in each example, are prepared in a rapid laboratory mixer. The quantities of the components are indicated in part by weight per 100 parts by weight of PVC (pcr). The quantities of organo-metallic halide and metal halide are, in addition, indicated in brackets by the content in halogen, expressed in milliequivents of halogen per kg of PVC.

Test method for determining the initial color, color stability and thermal stability.

A 60 gram portion of the mixture is subjected to kneading on a laboratory cylinder mixer, the cylinders of which are heated to 210 ° C. by circulation of oil. The diameter of the two cylinders is 250 mm. The distance between the cylinders is kept constant during the test at 0.6 mm. The respective rotational speed of the cylinders is 18 rpm and 20 rpm. A sample of a small rectangle is taken every minute of mixing. The samples are fixed successively on a cardboard display. The initial color is assessed visually on the sample at two minutes. Color stability is determined by the duration of mixing leading to a noticeable change in the original color. The thermal stability is determined by the mixing time leading to the color changing to dark brown or dark red.

The thiol compound, pentaerythritis tetra-mercaptoacetate is prepared in the laboratory by esterification of one mole of pentaerythritis containing approximately 4% of -OH functions, with four moles of mercaptoacetic acid, of iodometric purity of 99.96.

The acid is first introduced into the reactor with 2% water and 0.25% para-toluene sulfonic acid. At 80 ° C, pentaerythritis is added; then the temperature is maintained at 145 ° C until the release of water stops. ^' 0.25% of lime carbonate is then introduced and hot filtration is carried out.

Example 1

Components Mixtures

A B

PVC "Lacqvyl S 071 s", K = 58 from the company ATOCHEM 100 [00

BTA III F Shockproof from ROHf \ N & HAAS

Lubricant AC 316 A from ALLIED CHEMICAL 0.3 0.3

LA CERESINE Lacer B lubricant 0.45 0.45

Epoxidized soybean oil

Pentaerythritis tetra-mercaptoacetate

Mono-n-octyl tin tri-chloride (MOTCl) from the company SCHINGING 0.017 (1.45)

Test results

Color Mixture Stability Initial color thermal stability

yellowish less than 2 between 3 minutes and minutes 4 minutes

B yellowish 9 minutes 12 minutes 8 The addition of a very small amount of tri-chloride of mono-n-octyl tin quadruples the color stability and the thermal stability. Example 2

Mixing components

D

PVC "Lacqvyl S 071 s' ^! WO 100 100 100

BTA III F

AC 316A 0.3 0.3 0.3 0.3

Lacer BN 0.45 0.45 0.45 0.45

Calcium stearate 0.2 0.2 0.2 0.2

Zinc stearate 0.2 0.2 0.2 0.2

Epoxidized soybean oil 1 1 1 1 1

Pentaerythritis tetra-mercaptoacetate

0.017 (1.45) tin mono-n-octyl tri-chloride

Di-n-octyl tin chloride (DOTCD ^' from the company SCHERING 0.017 (0.82)

Irgastab 17 OK thio-organotin stabilizer from CIBA-GEIGY Test results

Mixture Color Stability Initial stability thermal color

yellow 8 minutes 14 minutes

D practical¬ 1 1 minutes 11 minutes ment 30 seconds colorless

E light yellow 1 1 minutes 12 minutes

F practical ¬ 1 1 minute 14 minutes colorless

We see, on the one hand, the very clear improvement in the initial color by the addition of organotin chloride and, on the other hand, the result obtained with mixture D quite comparable to that obtained with Irgastab 17 MOK stabilizer.

Example 3

Mixing components

H

PVC "Lacqvyl S 071 s" 100 100 100 100

BTA III F

AC 316A 0.3 0.3 0.3 0.3

Lacer BN 0.45 0.45 0.45 0.45

Calcium stearate 0.2 0.2

Zinc stearate 0.2 0.2

Epoxidized soybean oil 1

Tetra-mercaptoacetate - pentaerythritis 1

Mono- n-octyl tin trichloride 0.017 0.051 0.017 0.034

(1.45) (4.35) (1.45) (2.90)

Test results

Mixture Color Stability Initial stability thermal color

practical 8 minutes 9 minutes colorless

H practical ¬ 5 minutes 6 minutes colorless

yellowish 9 minutes 19 minutes

yellow 13 minutes 19 minutes clear

We see that :

- There is a limit on the rate of addition of organotin chloride, after which a reduction in color and thermal stability occurs.

- even in the presence of calcium soap, without the addition of zinc stearate, clear initial colors are obtained and excellent color and thermal stability.

Example 4

Components Mixtures

K M N

PVC "Lacqyvyl S 071 s" 100 100 100 100 100

BTA III F

AC 316 A 0.3 0.3 0.3 0.3 0.3

Lacer BN 0.45 0.45 0.45 0.45 0.45

Epoxidized soybean oil 1

Pentaerythritis 1 tetra-mercaptoacetate

CARLO ERB TPE Tetra-Chioride 0.0095 0.0285 (1.45) (4.35)

CARLO ERBA cadmium di-chloride RPE 0.0133 0.0399 (1.45) (4.35)

The metal halide is introduced into the mixture in the form of a very dilute aqueous solution by dissolving, in 250 cc of distilled water, 0.77 grams of SnCl. 5H ₂ 0 or one gram of chemically pure CdCl-2,5H_O. The solution of tin tetrachloride has, at a temperature of 23 ° C., a pH = 1.5 and that of cadmium dichloride a pH = 5. Before the test with a cylinder mixer, the mixtures were dried in the oven at 110 ° C for ten minutes. Test results.

Mixture Color Stability Initial stability thermal color

K yellowish inf. 4 minutes

2 minutes

yellowish between 8 and 1 1 minutes 9 minutes

M practically colorless S minutes between 9 and 10 m inutes

N yellowish inf. at between 5 and 6 minutes

2 minutes

O yellowish between 4 and 10 minutes

5 minutes

We can note that

- the tin tetrachloride gives color and thermal stability very close to those imparted by mono-n-octyl tin trichloride, at equivalent chlorine level.

_* - the effectiveness of cadmium dichloride is, at equal halogen content, much lower than that of tin tetrachloride, probably because of its weaker acidic character.

Claims

- CLAIMS -

1- Process for protecting mixtures based on polymers and / or halogenated copolymers against undesirable effects of heat during their passage through processing machines, characterized in that at least the mixtures are added during their preparation an organic compound containing one or more -SH functions and a very small amount of at least one halide chosen from organo-metallic halides and / or metal halides, or a mixture of these compounds.

2- Method according to claim 1, characterized in that the organic compounds containing one or more function (s) -SH, have the following general formula:

R (R '-SH x) y

in which :

- R is the remainder of a monohydroxyl alcohol chosen from aliphatic, olefinic, cyclic, heterocyclic, aromatic alcohols, or the remainder of a monomeric polyol such as: glycerol, glycol, pentaerythrite, sorbitol, pentites, hexites, monosaccharides, or the remainder of a polymeric polyol such as: polyethylene glycol, polypropylene glycol, polyvinyl alcohol, cellulose, starch and other polysaccharides, R optionally comprising functions such as etheroxide, carboxylic ester, thiocarbon, sulfonic or / and esters of other inorganic acids.

- R'-SH is the remainder of a monoaeide or of a polycarboxylic acid, containing one or more -SH functions linked to R by esterification, such as thioglycolic, mercaptopropyonic, mercaptosuccinic, dimercaptosuccinic, thiosalycillic acids .

- x indicates the number of -SH linked to R '.

- y indicates the number of R'-SH linked to R.

3- A method according to claims 1 and 2, characterized in that the organometallic halides have the following general formula:

R n Me (v) Hal v-n

in which :

- R is an aliphatic, linear or branched, cyclic, olefinic, heterocyclic organic residue. aromatic, whether or not containing radicals or / and simple or mixed functions.

- n indicates the number of R linked to the metal Me.

- Me = Sn, Al, B, Sb, Fe, Cd, Zn, Cu, Ti, Hg, Bi, Mn or Ga.

- v is the valence of Me. - Hai = chlorine, bromine, iodine, fluorine.

4- Method according to claims 1 and 2, characterized in that the metal halides have the following general formula:

Me (v) Hal

in which :

- Me is '^' a metal, the halogen compound of which gives an aqueous solution of approximately 35 meq. of halogen per liter of distilled water, at around 23 ° C, a pH equal to or less than 5, preferably a pH equal to or less than 3.

- v is the valence of Me.

- Hai = chlorine, bromine, iodine, fluorine.

5- Method according to claim 4, characterized in that the metal is tin.

6- Method according to one of the preceding claims, characterized in that the added amount of organic compound containing one or more -SH function (s), is between 0, 1 and 5 parts by weight per 100 parts by weight of resin and preferably between 0.3 and 1.5 parts by weight per 100 parts by weight of resin.

7- Method according to one of the preceding claims, characterized in that the added amount of halogenurfe (s) expressed by its halogen content, is between 0, 1 and 30 meq. (milliequivalent of halogen) per kg of resin, preferably between 0.3 and 10 meq. per kg of resin.

8- Method according to one of the preceding claims, characterized in that the mixtures to be protected are chosen from mixtures based on homopolymers and / or copolymers of vinyl chloride, vinyiidene chloride, chloro-fluoroethylene, comonomers of the copolymers being chosen from vinyl acetate, acrylonitrile, maleic anhydride, ethylene, propylene and / or any other monomer copolymerizable with said vinyl halides, as well as halogenated polyolefins and other resins and elastomers, natural or synthetic, halogen.

9- Method according to one of the preceding claims, characterized in that the mixtures also contain usual additives such as anti-shock, plasticizers, processing aids, lubricants, fillers, dyes, known thermal stabilizers, antistatic.

10- thermal stabilizer systems for the protection of resins according to claim 8, characterized in that they contain at least one halide according to one of claims 1, 3, 4, 5 and 7, in combination with one or more organic compounds containing -SH functions according to one of claims 1, 2 and 6.

11- Powder, granule, paste, or any other physical form mixtures, the protection against the effects of heat during processing has been achieved by the use of a system of thermal stabilizers according to the any one of claims 1 to 10.