JPH0240258B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to the thermal stabilization of halogenovinyl resins, particularly polyvinyl chloride. The present invention includes a method comprising adding into the polymer an additive that reduces the harmful effects of heat on the polymer. The invention also relates to plastics obtainable by applying the process of the invention to various polymers containing halogen vinyl units. More particularly, it relates to plasticized materials consisting of such polymers or copolymers. The recent effort to produce halogenovinyl polymers that are subject to as little alteration as possible under the influence of heat has always been an issue of interest to industries that produce or utilize such materials. As for polyvinyl chloride, the most important of this type of material, its thermal stability has been a research goal for 50 years. The production of polyvinyl chloride is usually done under heating.
Since it is carried out at 150-200℃, the decomposition reaction accompanied by the release of HCl and the scission of macromolecular chains causes mechanical damage to the product.
It reduces the rheological and electrical properties and at the same time causes the product to discolor and rapidly turn black. Over the past half century, various additives have been used to suppress this difficult decomposition reaction. The first stabilizers were alkaline earth metal soaps and lead compounds, especially silicates. Other metal derivatives are subsequently used and then stabilized step by step by the addition of second compounds or co-stabilizers such as epoxides, phosphites, phenolic antioxidants, organothio compounds, etc. completed. Furthermore, during the past decade, great advances have been made in stabilizers through the use of systems consisting of Cd salts and Ba or Ca salts. Since 1970, more than 80 stabilizers of this type have been developed, such as Advastab, Ferro. It is commercially available under various trade names such as Ferro Mark, Synpron, etc. (Modern Plastics Encyclopaedia, 1970−
1971, pp. 870-875). However, as cadmium is toxic and expensive, other stabilizers have been investigated and other systems have been used, namely Ba and Zn compounds or
Compounds of Ca and Zn have been produced, and many products are currently in use. On the other hand, since good results were obtained with organotin and Sb derivatives, efforts were made to further improve these results, and patents such as French Patent No. 2434835 and West German Patent No. 1217609 or U.S. Pat. The addition of certain mercaptans has been found to be interesting, as shown in US Pat. No. 3,063,963. However, for health and cost reasons, there is currently a trend to replace heavy metals, namely Cd and Sn, with completely non-toxic and inexpensive stabilizers. That is, there is currently a desire to return to alkaline earth metal and zinc systems and enhance the stabilizing effect with other additives. Representative examples of such efforts are found in French patent application no. 2492391 (1980) and European patent application no. Thus, improved stabilizers are disclosed. European patent applications indicate the addition of polyols. However, conventional stabilizers, of whatever nature, can only cause thermal deterioration and, if required, visible light or other radiation deterioration, and do not completely undergo decomposition reactions. Since there is no suppression of this, no conclusive results have been obtained to date. Therefore,
It is hoped that some research will provide an opportunity to improve upon the prior art. The present invention results from the research conducted in accordance with the above new trends and provides a distinct improvement in the heat resistance of halogenovinyl resins. An unexpected feature of the present invention is that -SH in the molecule of mercaptoester used in the prior art
This is due to the fact that by adding certain mercaptoesters to the resin, which reduce the relative number of groups, improvements in thermal stability have been obtained more economically and also with almost no odor. The use of mercaptoesters in general and polyol mercaptoesters in conjunction with stabilizing metal compounds is known from French Patent No. 2,492,391 and US Pat. No. 3,144,422. The effect depends on the ratio of stabilizer in the resin,
That is, it increases with the content of -SH groups. However, it has been surprisingly found according to the invention that when a mercaptoester containing fewer -SH groups than alcohol residues is used, the resin therefore
With fewer mercapto groups per 100 parts, the stabilization is at least good, or even better, and it is also more economical. An advantage of the present invention is that it provides plastics that are stable and of similar quality to materials containing Cd or Sn compounds, while using cheaper and non-toxic additives. Furthermore, the plastic stabilized according to the present invention has no odor compared to plastics containing conventional thioglycol esters, and does not contain the hydroxyl group-containing additives used in the above-mentioned prior art. Water resistance is also good. The method of the present invention, which consists in adding to a halogenovinyl resin an organic acid ester containing mercapto groups of one or more polyols, provides that in these esters only a portion of the polyol -OH groups are oxidized by the mercapto acid. esterified,
On the other hand, other -OH groups are characterized in that they are esterified with sulfur-free organic acids. According to a preferred embodiment of the invention, the mixed esters of mercapto and non-mercapto acids are supplemented with other stabilizers or additives known per se, in particular alkaline earth metals and/or B, A of the periodic table. , A and organic compounds of group A metals, and fatty compounds, preferably oxides, can be used in combination. The stabilizers according to the invention are particularly effective for plastic resins. Preferably, the metal of groups 1 to 3 is zinc, but other metals can also be chosen, especially antimony, silicon or aluminium. The most suitable alkaline earth metal is
Ca, Ba and/or Sr. Mercapto acid esters have several different acid residues on the same polyol residue, including -SH groups and/or some acids without -SH groups. The mercapto acid forming the mixed ester used in the present invention is generally represented by the following formula. (HS) _o -R-(COOH) _n where n is 1 to 5, m = 1 or 2, and R is a _C1 to _C35 aliphatic chain or ring, or a branched chain. preferably from _C2 to _C17 ,
When m=1, R corresponds to the total number of each of _C2 to _C36 and _C3 to _C18 . By way of non-limiting example, various mercapto acid esters used in the present invention are as follows. α-mercaptopropionic acid (or 2-mercaptopropionic acid) β-mercaptopropionic acid (or 3-mercaptopropionic acid) HSCH ₂ CH ₂ CO ₂ H ω-mercaptoundecanoic acid (or 11-mercaptoundecanoic acid) HSCH ₂ (CH ₂ ) ₉ CO ₂ H 10-mercaptoundecanoic acid Mercaptosuccinic acid (or thiomalic acid) dimercaptosuccinic acid 2-mercaptobenzoic acid (or thiosalicylic acid) As mentioned above, the other portion of the -OH groups of the polyol from which the mercaptoesters have been derived are esterified with other carboxylic acids that do not have -SH groups. Such carboxylic acids have the general formula R'(CO ₂ H) _p and are preferably mono- or diacids (p=1 to
2). R' is a straight-chain or branched aliphatic alkyl or alkenyl or aromatic group containing at least two carbon atoms, preferably from _C5 to _C37 , most preferably from _C5 to _C17 . Any carboxylic acid can be used, but fatty acids are preferred, especially caprylic acid, octanoic acid, cetanoic acid, pelargonic acid, capric acid, undecanoic acid, lauric acid, myristic acid, palmitic acid, stearic acid, isostearic acid, These are oleic acid, linoleic acid, linolenic acid, behenic acid, and montanic acid. Other particularly suitable acids are succinic acid, adipic acid,
Aromatic monocarboxylic acids such as glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dioleic acid, malic acid, tartaric acid or phthalic acid and benzoic acid. The polyols from which the mixed mercaptoesters used in the present invention are derived are formed by linear or branched carbon chains or rings and are generally C _2
-C30 , preferably _C2 - _C20 , with more than or equal to 2 OH groups. Various other functional groups may also be included, particularly ether oxides, thiols, sulfides, disulfides, polysulfides, carboxylic acids, esters, and amines. Non-limiting examples of polyols include the following compounds. Ethylene glycol Polyethylene glycol HO (-CH ₂ CH ₂ O) - _r CH ₂ CH ₂ OH r = 1 to 30 Propylene glycol Polypropylene glycol Thiodiglycol HOCH ₂ CH ₂ SCH ₂ CH ₂ OH Pentaerythritol C (CH ₂ OH) ₄ Dipentaerythritol (HOCH ₂ ) ₃ C−CH ₂ OCH ₂ C (CH ₂ OH) ₃ Tripentaerythritol (HOCH ₂ ) ₃ C−CH ₂ OCH ₂ C
(CH ₂ OH) ₂ CH ₂ OCH ₂ C (CH ₂ OH) ₃ Trimethylolpropane CH ₃ CH ₂ C (CH ₂ OH) ₃ Glycerol HOCH ₂ CH (OH) CH ₂ OH Thioglycerol HSCH ₂ CH (OH) CH ₂ OH or HOCH ₂ CH(SH)CH ₂ OH Butanediol-1,2, Butanediol 1,
3. Pentol, hexol, etc. Polyol residues, which form a necessary part of the mercaptoesters according to the invention, can also carry monoalcohol groups. In fact, it is advisable to reduce the molecular weight of the ester when a polyacid is used. In this case, a portion of the carboxyl groups of the polyacid are preferably esterified with monoalcohols. Monoalcohols are generally _C1 to _C20 , preferably _C2 to _C8 . Such treatment is particularly effective when the mercaptoester has a molecular weight of 1200 or more. Non-limiting examples of mixed esters for use in the present invention are shown below. Pentaerythrityl tris(3-mercaptopropionate) monocaprate Pentaerythrityl mono(2-mercaptopropionate) triscaproate Pentaerythrityl tris(3-mercaptopropionate) monostearate Pentaerythrityl bis(3-mercaptopropionate) bispelargonate Trimethylpropane bis(3-mercaptopropionate) monooctanoate Ethylene glycol 3-mercaptopropionate-laurate Pentaerythrityl bis(thioglycolate)
Bispalmitate Glyceryl bis(3-mercaptopropionate) monooleate Glyceryl bis(3-mercaptopropionate) monooctanoate

[expression] and/or

[Formula] Thioglyceryl mono(3-mercaptopropionate) monooctanoate

[expression] and/or

[expression] and/or

[Formula] Fatty compounds which can advantageously be present in the composition of matter stabilized according to the invention are generally one or more preferably epoxidizable unsaturated C _{8 C1} - _C12 alkyl esters of glycols and/or glycerol with _~C24 fatty acids. Natural oils such as epoxidized linseed oil, soybean oil or fish oil are preferably used for this purpose. The minimum molecular weight of mixed mercaptoesters is 178, which corresponds to the lightest acids mercaptoacetic acid and acetic acid, and the lightest polyol ethylene glycol. That is, this minimal mixed ester is represented by HS- _CH2COO - _{CH2CH2 - OOCCH3} . The preferred minimum mercaptoester molecular weight is
206 and is ethylene 1-mercaptopropionate-2-propionate. HS−CH ₂ CH ₂ COO−CH ₂ CH ₂ −OOC−
As CH ₂ CH ₃ heavy esters, mention may be made, for example, of mixed fatty acid mercaptoesters of sugars, in particular glucose tris(mercaptostearate) bisstearate. Regarding the molecular weight of the mercaptoester used, it ranges from 178 to about 2000, preferably from 200 to about 2000.
It is 1000. For example, pentaerythrityl bis(mercaptopropionate) bisoctanoate, which gives excellent results, has a molecular weight of 564. The object of the present invention is to esterify at least one OH group of the polyol with an organic acid without -SH groups, while all or some of the other -OH groups are esterified with a mercapto acid. This is achieved by esterification. Conversely, mixed esters in which the molecule has a single mercapto acid and no other acids -SH are suitable for stabilization. In the most common examples of esters derived from polyols with 2 to 6 -OH groups, there is 1 metalpt acid residue for every 1 to 5 acid residues without -SH groups, or vice versa. Mercapto acid residues 1-5
1 non-mercapto acid residue per. Among the organic compounds of alkaline earth metals and various zinc compounds, carboxylates, mercaptides and ZnCl ₂ are of particular note. Among the carboxylic acid salts, notable non-limiting examples include caproate, 2-ethylhexanoate, otatanoate, pelargonate, laurate, palmitate, stearate, oleate, penzoate, phenate, alkyl phenate, naphthenate. and neoalkanoates. Among the mercaptides, aliphatic mercaptans,
Mention may be made of mercaptides derived from mercapto acid esters or mercaptoalkyl esters. However, some derivatives such as carbonates, oxides, hydroxides, sulphates, halides (chlorides, bromides) can also be used advantageously. The present invention is applicable to various halogen vinyl polymers and copolymers, especially polyvinyl chloride, polyvinylidene chloride, polyvinylacetochloride, perchlorinated polyvinyl chloride and chlorofluorovinyl resins, etc., but especially polychlorinated Vinyl-based plastics are important. As is known in the art, the proportion of the first stabilizer, which is a combination of an alkaline earth metal organic compound and a zinc organic compound, is most preferably 0.01 to 6% by weight relative to the resin to be stabilized. is 0.05-3%
It is. When the mixed mercaptoesters according to the invention are used as co-stabilizers, they do not have to be equal to the proportion of the first stabilizer, but are within the same range as the proportion of the first stabilizer. In the case of polyvinyl chloride plasticized by the addition of plasticizers consisting of esters, in particular phthalates, adipates, sebacates, azelates, phosphates or polyesters, the resin
The ratio per 100 parts by weight is preferably as follows. 5 to 70 parts of plasticizer, 1 to 10 parts of fatty compound, 0.1 to 2 parts of alkaline earth metal organic compound, 0.05 to 1.5 parts of Zn organic compound, 0.1 to 3 parts of mixed mercaptoester. The ratio of alkaline earth metal to zinc compound is 1 to 6 mol of the former per 1 mol of the latter. For calcium, the optimal ratio is per atom of Zn
Ca1 to 4 atoms. In the following non-limiting example, samples of polyvinyl chloride stabilized with additives according to the invention were subjected to a heat-induced discoloration test. First, various compositions were mixed on a roller mixer,
The mixture was kneaded at 160°C for 5 minutes. The resulting sheet had a thickness of about 1 mm. A Sigma type furnace manufactured by Metrastat Société Anonymous (SA) was used for thermal testing. The test method involves a stepwise change in color based on the thermal decomposition of a 25 cm long strip-shaped specimen cut from the above sheet and temporarily exposed to heat in a furnace maintained at a constant temperature. This was done by observing. The plate with the sample placed on it is moved outside the furnace,
A device is provided consisting of an electromechanical system for dispensing the furnace at a preset constant rate, an electronic control assembly for regulating the speed of the plate and also regulating the temperature of the furnace. Resin discoloration was observed at a given furnace temperature and sample removal rate. For each test, the "stabilization time", ie the time at which the resin turned black or the Yellow Index was recorded, was recorded. The composition used in the test is as follows. 100 parts by weight of polyvinyl chloride (commercially available as Lacqviyl S.111, Index K = 67). 40 parts by weight of dioctyl phthalate (trade name: Palatinol AH). Examples 1-5 Heat resistance tests were conducted at 190°C. The sample removal speed was adjusted to 30 minutes. The results are shown in Table 1 below. % indicates the proportion of additives added to the sample before passing through the oven.

[Table] The first conclusion drawn from the results in Table 1 is that the mixed mercaptoester (bis-bis) of Example 3
is Example 2 (tetrakis) with corresponding -SH content
The yellow index is 127 compared to 135 in Example 2, which is at least better than Example 2, or slightly better. Therefore, the use of this mixed ester compound is more economical. A second interesting result is obtained from Examples 4 and 5. That is, in the presence of epoxidized soybean oil, mixed mercaptoesters (Example 5)
significantly reduces the yellow index from 155 to 90. Examples 6-10 Mixed mercaptoesters were combined with standard stabilizers based on metal compounds. The exam is
It was carried out at 190℃. The results are shown in Table 2 below.

[Table] From the above test, the mixed mercaptoesters (bis-bis) of Examples 8 and 10 have only half the number of -SH groups than the mercaptoester (tetrakis) of Example 7. Despite this, it is clearly more effective. For the combination of mixed esters and standard Ba and Zn stabilizers (Example 9 versus Example 10) a very significant improvement in stability of (53-43):43=23.2% is evident. Examples 11-19 The procedures of the previous examples were followed except that the plasticizer, dioctyl phthalate, was used in an amount of 50 parts by weight per 100 parts by weight of resin. In addition, the resin contains epoxidized soybean oil 5
%, Ca stearate 0.3%, Zn stearate 0.15
% was added. 190℃ with addition of various mercaptoesters
Stability is expressed in minutes. The results are shown in Table 3. The results in Table 3 show that mixed mercaptoesters
By combining an epoxidized oil and a standard stabilizer consisting of Ca and Zn stearate, the stability was increased by approximately 30% (from 160 in Example 11 to
226 in Examples 14 and 16). The results in Table 3 also show that mixed mercaptoesters have surprising advantages compared to regular mercaptoesters. Example 14 (mixed ester) is similar to Example 13 (mercapto alone) despite its low -SH content.
gives good results as well.

[Table] In comparing Examples 13 and 14, Example 14 is
Since it is less than half of the compound in Example 13, Example 14 is
A good comparison is with Example 12 with 0.5% mercaptoester. However, the stability in this case was determined by the addition of additives according to the invention (Example 14)
It is 203 minutes (Example 12) compared to 226 minutes according to the method. Similar conclusions can be drawn from the comparisons of Examples 15 vs. 16 and 17 vs. 18. Conventional mercapto-acetate (Example 17)
It should be noted that in this case, the resin had an odor. Example 19 shows that mercaptoesters of monoalcohols are less effective than mercaptoesters of polyols. Examples 20-23 Using the method of the previous example, the nature and ratio of the stabilizer was determined for the same composition of polyvinyl chloride containing 50% dioctyl phthalate and 5% epoxidized soybean oil. Changed. Examples 20 to 22 use Ca and Zn compounds,
On the other hand, in Example 23, conventional stabilizers based on Ca and Ba were used. The results are shown in Table 4.

[Table] The results in Table 4 show that with the addition of mercaptoester, stability equivalent to that provided by the known Cd, Ba system is achieved, and in addition,
This shows that it has the advantage of being extremely cheap and avoiding all the toxicity caused by heavy metals. Examples 24-26 A resin composition consisting of 50 parts of dioctyl phthalate and 5 parts of epoxidized soybean oil per 100 parts of polyvinyl chloride, further containing 0.6% Balaurate and 0.15% Zn stearate as standard stabilizers. Using. The heating furnace is controlled at 190℃, and the sample removal speed is 180℃.
It was warm at ℃. The stabilities shown in Table 5 below were obtained for each of the co-stabilizers used at three different concentrations. That is, in the case of 0.5% co-stabilizer in Example 24, 139-105=34, or (34:105)100=
There was a 32.3% increase in stability.

[Table] Also, in Example 25, 153-105=48, or (48:
105) 100 = 45.7%, whereas in Example 26 using a normal mercaptoester, 131-
It was only 105=26, or (26:105)100=24.8%. Example 27 Examples 8 and 10 were repeated using ZnCl ₂ instead of Zn octanoate. In fact, similar results were obtained. Examples 28 and 29 Polyvinyl chloride 100
parts, 50 parts of dioctyl phthalate, 5 parts of epoxidized soybean oil, 0.6 parts of Ba octanoate and
A mixture of 0.04 parts of ZnCl ₂ was used. Operating temperature 190℃, sample removal speed 180 minutes. The obtained times are as follows. Example 28, no other additives. 84mn Example 29, Pentaerythrityl bis(3-mercaptopropionate)bis
137mn, 1 part octanoate added. Or 60% improvement. Example 30 An unplasticized polyvinyl chloride containing only pentaerythrityl bis(3-mercaptopropionate) bisoctanoate was tested. Operating temperature 160℃. The yellow index was 90, and the control without additives was 101.

Claims (1)

[Scope of Claims] 1 A part of the hydroxyl groups of a C ₂ to C ₆ chain polyol having 2 to 6 hydroxyl groups is a mercaptocarboxylic compound represented by the formula (HS) _o -R-(COOH) _n (). esterification with an acid to convert all or a portion of the hydroxyl group to the formula
At least one of the mixed mercaptoesters of the polyol obtained by esterification with a carboxylic acid having no -SH group represented by R'(COOH) _p ()
A method for thermally stabilizing halogenovinyl resin, which comprises adding seeds into the resin. However, in the above formula (), n and m are each 1 or 2, R is a C ₁ to _{C 12} aliphatic chain or ring, p is 1 or 2, and R' is C ₅ to _C17 alkyl group, alkenyl group or aromatic group, and the mixed mercaptoester has one mercaptocarboxylic acid residue per 1 to 5 residues of the carboxylic acid that does not have the -SH group, Alternatively, there is one carboxylic acid residue not having the -SH group per 1 to 5 residues of the mercaptocarboxylic acid. 2 The carboxylic acid without -SH group is C ₆ - C ₁₈
The method according to claim 1, wherein the aliphatic carboxylic acid is an aliphatic carboxylic acid. 3. Claim 1 or 2, wherein the mixed mercaptoester has a molecular weight of 178 to 2000.
The method described in section. 4. Claim 1 or 2, wherein the mixed mercaptoester has a molecular weight of 200 to 1000.
The method described in section. 5. A combination of the mixed mercaptoester with a compound of at least one metal selected from Group B, A, Group A, and Group A metals of the Periodic Table of the Elements, and at least one alkaline earth metal organic compound. 5. A method according to any one of claims 1, 2, 3 and 4, wherein: 6 0.1-3% mixed mercaptoesters per weight of the resin are added together with 0.05-1.5% organic Ca, Mg or Ba compounds and 0.05-2.5% Zn compounds, with an alkaline earth metal content per atom of Zn. 9. The method for thermally stabilizing a halogenovinyl resin according to claim 8, which contains soybean oil having 1 to 3 atoms and in which plasticized polyvinyl chloride is epoxidized.