JPH0337578B2 - - Google Patents

Description

[Detailed description of the invention]

Halogen-containing polymers, especially chlorine-containing polymers, have gained a high degree of industrial importance and use. especially,
Polyvinyl chloride (PVC) is widely used in packaging, siding, pipes, and extrusions. PVC
Such large-scale and widespread use of halogen-containing polymers, such as those typified by , is at least in part the result of the stabilization of such polymers against light and/or heat-induced degradation. During processing or use, PVC deteriorates due to long-term exposure to light and/or heat, with concomitant darkening or discoloration and changes in physical properties (e.g. tensile strength, flexural strength, impact strength). ) is known to cause losses. Such deterioration
Reduces the usefulness of PVC and limits the conditions and equipment for processing and manufacturing PVC products. Thus, for example, the service life of PVC products is very limited, the conditions of use of PVC products are severely restricted and the manufacturing conditions are extremely narrow. One particularly troublesome form of degradation of halogen-containing polymers occurs when they are processed into products in a manner that uses heat to melt or soften the polymer. Discoloration of the polymer occurs during the first few minutes (eg, about 1-10 minutes) of processing at high processing temperatures (eg, about 175-200°C). This discoloration during the first few minutes of exposure to high processing temperatures is commonly referred to as early color or early discoloration.
Avoidance of such initial color or discoloration is extremely important in many applications (eg, plastic pipes), and is particularly important when white or light colored products are to be made. It is, of course, also important to prevent or reduce discoloration and degradation of organic polymers during prolonged exposure to high processing temperatures, such as encountered in certain processing or manufacturing methods. This prolonged exposure to high processing temperatures can lead to rapid and catastrophic decomposition of the polymer, turning it into a pit-like wear material, and especially in the case of halogen-containing organic polymers, corrosive substances in the processing equipment, e.g. May result in HCl formation. This wear and corrosion ruins the highly polished interior surfaces of the processing equipment, rendering the equipment virtually unusable. In order to prevent or reduce discoloration and deterioration of halogen-containing polymers during processing at high temperatures and during exposure to high temperatures under the conditions of use of the manufactured products, the prior art uses various substances known as stabilizers. is added to the polymer. The most prominent of these stabilizers are organotin stabilizers. These organotin stabilizers are known to be particularly effective in preventing initial discoloration of halogen-containing polymers. However, although organotin stabilizers have the ability to reduce or prevent early discoloration, they have become increasingly expensive in recent years, with the result that lower priced products such as pipes cannot afford the cost of such stabilizers. It's coming. Attempts have been made to replace some or all of the organotin stabilizers with lower cost materials. Thus, various combinations of organotin compounds and other organometallic compounds have been developed. One such combination, described in JP-A-52-37956 to Minagawa et al., includes at least one alkyltin compound selected from monoalkyltin compounds and dialkyltin compounds and at least one mercaptide or mercaptocarboxylic compound. Acid salts or esters or maleic acid and Mg, Ca, Sr, Ba,
Contains a salt or ester with a metal selected from Zn, Sn or Zr. As an alkyltin compound,
For example, compounds such as dimethyltin oxide, dimethyltin sulfide, dibutyltin bis(isooctylmercaptoacetate), monobutyltin tris(isooctylmercaptopropionate) are described. Salts or esters of metal mercaptides or mercaptocarboxylic acids include, for example, compounds such as zinc bis(isooctylthioglycolate). Complete removal of organotin compounds was attempted in JP-A No. 52-89451 by Shinkawa, using a halogen-containing resin containing an organozinc compound and an alkali metal salt or an alkaline earth metal salt of an organic acid. Stabilizers for use are described. Organozinc compounds have the formula Zn(SX)(Y) where SX is a mercaptan or mercaptate residue and Y is the same as SX or an organic acid residue. Examples of such organozinc compounds are It is. Similarly, U.S. Pat. No. 2,723,965 to Leistner et al. describes the formula metals, examples of which are alkaline earth metals,
It describes stabilizers for halogen-containing polymers, which are organometallic compounds containing cadmium, lead, zinc, and tin. The present invention provides a novel composition comprising: 1) at least one zinc mercaptoester; 2) at least one basic inorganic alkali metal compound or basic inorganic alkaline earth metal compound; and optionally 3) at least one substituted dihydropyridine. relating to things.
These compositions are useful as stabilizers for halogen-containing polymers. The present invention also provides a halogen-containing polymer, at least one zinc mercaptoester, at least one basic inorganic alkali metal compound or basic inorganic alkaline earth metal compound, and optionally at least one substituted dihydropyridine. Novel polymer compositions with improved resistance to discoloration due to heat exposure during processing, including:
These polymer compositions are useful in making rigid products such as pipes. We have now discovered, in accordance with the present invention, stabilizer compositions that have improved effectiveness in stabilizing halogen-containing polymers against the degrading effects of heat. Polymer compositions with improved resistance to discoloration due to heat exposure during processing are also provided by the practice of the present invention. The present invention comprises a) 1) at least one zinc mercaptoester, 2) at least one basic inorganic alkali metal compound or basic inorganic alkaline earth metal compound, and optionally 3) at least one substituted dihydropyridine. and b) 1) a halogen-containing polymer; and 2)
at least one zinc mercaptoester;
3) at least one basic inorganic alkali metal compound or basic inorganic alkaline earth metal compound; and optionally 4) at least one substituted dihydropyridine. Halogen-containing polymers stabilized by the stabilizer compositions of the present invention and useful in the polymer compositions of the present invention include, for example, halogenated polyolefin homopolymers, halogenated polyolefin copolymers, halogenated polyolefin homopolymers, or halogenated polyolefin homopolymers. Included are polymer blends comprising polyolefin copolymers, halogenated vinyl homopolymers, halogenated vinyl copolymers, halogenated vinyl homopolymers, or halogenated vinyl copolymers. Polymer blends comprising halogenated vinyl homopolymers, halogenated vinyl copolymers, halogenated vinyl homopolymers or halogenated vinyl copolymers that can be used in the practice of the present invention include, for example:
(1) Polyvinyl chloride, polyvinylidene chloride, polyvinyl bromide, polyvinyl fluoride, polyvinylidene fluoride, (2) vinyl chloride, vinylidene chloride, vinyl acetate, vinyl butyrate, vinyl benzoate, diethyl fumarate, Diethyl maleate, other alkyl fumarates and alkyl maleates, vinyl propionate, methyl acrylate, 2-ethylhexyl acrylate, butyl acrylate, ethyl acrylate and other alkyl acrylates, methyl methacrylate, ethyl methacrylate, butyl methacrylate,
Hydroxyethyl methacrylate and other alkyl methacrylates, methyl α-chloroacrylate,
Styrene, vinyl ethers such as vinyl ethyl ether, vinyl chloroethyl ether, vinyl phenyl ether, vinyl ketones such as vinyl methyl ketone, vinyl phenyl ketone, 1-
Copolymers with copolymerizable ethylenically unsaturated monomers such as fluoro-1-chloroethylene, acrylonitrile, chloroacrylonitrile, allylidene diacetate, chloroallylidene diacetate, ethylene, propylene, and (3) polyvinyl chloride and polyethylene. , polyvinyl chloride and chlorinated polyethylene, polyvinyl chloride and polymethyl methacrylate, polyvinyl chloride and polybutyl methacrylate,
Polymer blends can be used, such as blends of polyvinyl chloride and polystyrene, polyvinyl chloride and acrylonitrile-butadiene-styrene copolymers, polyvinyl chloride, polyethylene, and polymethyl methacrylate. Typical halogenated vinyl copolymers that can be used in the present invention include:
Vinyl chloride-vinylacetate (87:13), vinyl chloride-vinylidene chloride (95:5), vinyl chloride-diethyl fumarate (95:5), vinyl chloride-trichloroethylene (95:5), vinyl chloride:acrylic acid 2 - Contains ethylhexyl (80:20). Polymer blends that can be used in the practice of this invention consist of a physical blend of at least two different polymer species and contain from 25 to 95 weight percent vinyl halide homopolymer. Halogenated vinyl copolymers that can be used in the practice of this invention are copolymers containing 25 to 95 mole percent vinyl halide units. Zinc mercaptoesters useful in the practice of this invention are organozinc compounds having two mercaptoester groups, each bonded to a zinc atom by a sulfur atom, and having the formula () [In the above formula (), x = 1 or 2, and R
is a C ₁ to C ₂₀ linear or branched, saturated or unsaturated alkyl group. Examples of zinc mercaptoesters useful in the practice of this invention include, but are not limited to, the compounds shown in Table 1.

【table】 ‖
D Zn(SCH ₂ CH ₂ COC ₁₈ H ₃₅ ) ₂
O
‖
E Zn(SCH ₂ COC ₂ H ₅ ) ₂
As used herein, the term basic inorganic alkali metal compound or basic inorganic alkaline earth metal compound refers to an alkali metal or alkaline earth metal oxide, hydroxide, sulfide, silicate, phosphate, selected from the group consisting of borates. Preferably, the alkali metal is selected from Li, Na, K,
The alkaline earth metal is selected from Mg, Ca, Sr, and Ba. Basic inorganic alkali metal compounds or basic inorganic alkaline earth metal compounds include Ca(OH) ₂ , Mg
Examples include, but are not limited to, (OH) ₂ , LiOH, Na ₃ BO ₄ , K ₂ CO ₃ , and sodium silicate. As used herein, the term substituted dihydropyridine refers to a heterocyclic ring , and has a methyl group attached to the carbon atoms next to the ring nitrogen, that is, the 2nd and 6th positions, and an ester group attached to the 3rd and 5th positions of the ring. More specifically, these substituted dihydropyridines have the formula () [In the above formula (), R ² is a C ₁ to C ₂₀ linear or branched, saturated or unsaturated alkyl group.] Substituted dihydropyridines useful in the practice of this invention and methods for their preparation are described in Pigerol et al., US Pat. No. 4,209,439, which is incorporated herein by reference. Examples of substituted dihydropyridines useful in the present invention include, but are not limited to:

TABLE The amount of each component in the stabilizer compositions of the present invention can vary over a wide range. However, in general, the stabilizer composition will contain about 15% to about 85% by weight, preferably about 40% to about 85%, based on the total weight of the stabilizer composition.
60% by weight zinc mercaptoester and about 15 to ca.
85% by weight, preferably from about 40 to about 60% by weight, of a basic inorganic alkali metal compound or basic inorganic alkaline earth metal compound, and if used, from about 1 to about
50% by weight, preferably from about 10 to about 30% by weight of substituted dihydropyridine. Similarly, the amount of stabilizer composition used in practicing the polymer compositions of this invention can vary over a wide range. It is only necessary that at least a stabilizing effective amount of the stabilizer composition be present in the polymer composition. Generally, small amounts of the stabilizer composition, such as 0.05 parts by weight per 100 parts by weight of halogen-containing polymer, are effective for stabilization. There is no critical upper limit to the amount of stabilizer composition that can be used, but approximately
Amounts of the stabilizer composition in excess of 15 parts by weight do not provide increased effectiveness to compensate for the extra stabilizer usage.
Preferably, the stabilizer compositions of the present invention are used in an amount of about 0.2 to about 7 parts by weight per 100 parts by weight of halogen-containing polymer. In the practice of the polymer composition of the present invention, in addition to the halogen-containing polymer and the stabilizer composition, fillers, pigments, plasticizers, etc. known in the plastics art,
Customary additives such as dyes, lubricants, antioxidants, UV stabilizers may also be present. As fillers, materials such as calcined clay, calcium carbonate, and talc can be used. Substances such as titanium dioxide, carbon black, and iron oxide are
Can be used as a pigment. Known plasticizers that can be used include phthalates, sebacates, adipates, phosphates,
Includes fatty acid esters having 16-150 carbon atoms. Known lubricants that can be used include hydrocarbon waxes, stearyl stearate, cetyl palmitate and other ester waxes. Useful antioxidants include tricresyl phosphite, 2,6-di-t-butyl-4-methylphenol, 2,6-di-t-butyl-4-decyloxyphenol, 2-t-butyl-4 -Contains octadecyloxyphenol. The stabilizer compositions of the present invention can be manufactured using conventional equipment and methods known in the art. The components can be mixed together in any convenient manner and in any order that uniformly disperses each component throughout the mixture. The polymer compositions of the invention can be manufactured in a manner known in the art and using conventional equipment, such as a Henshel blender. One such method consists of mixing a premixed stabilizer composition with the halogen-containing polymer on a two roll mill. In another method, the stabilizer composition can be added to the halogen-containing polymer while continuously mixing in a Henschel blender. The important thing to consider is:
The stabilizer composition and the halogen-containing polymer are thoroughly mixed together. The stabilized halogen-containing polymer composition of the present invention can be used in the manufacture of products such as pipes. A variety of conventional molding techniques can be used to mold the stabilized polymer compositions of the present invention into the desired shape. The present invention will be explained below with reference to Examples. Unless otherwise indicated, all amounts and parts and percentages in the examples and throughout the specification are by weight. Example: Henschel high-intensity mixer (Henschel high
Intensity mixer (Type 2JSS), polyvinyl chloride (BF Gutsudoritsuchi Chemical Company (BF
GEON 103EP-F-76 (GEON 103EP-F-
76)] 3.0 parts of fine-grained calcium carbonate coated with 100 parts of calcium stearate, titanium dioxide
1.0 parts, 1.2 parts of paraffin wax (ADVAWAX 165, commercially available from Carstab Corporation),
0.60 part of calcium stearate, 0.15 part of oxidized low molecular weight ethylene homopolymer (AC629A, commercially available from Allied Chemical Corporation) and each of the stabilizer compositions shown in Table A in the order shown in Table A. Several mixtures are prepared by dry mixing at 110° C. with the amounts indicated in Table 1, which are parts by weight based on 100 parts of polyvinyl chloride. The resulting mixture is masticated on a two roll mill at about 193°C.
Samples are taken at 1 minute intervals starting when the mixture is first introduced into the mill. Evaluate the appearance of each sample taken from the mill using the scale below.

【table】 The results of these tests are shown in Table A.

【table】

【table】

Claims (1)

[Claims] 1 A formula () [In the above formula (), x is 1 or 2, and R is a C ₁ to C ₂₀ linear or branched, saturated or unsaturated alkyl group]; B. A composition for stabilizing a halogen-containing polymer against the deteriorating effects of heat, comprising at least one basic inorganic alkali metal compound or basic inorganic alkaline earth metal compound. 2 formulas (wherein ^R2 is a _C1 - _C20 straight-chain or branched, saturated or unsaturated alkyl group) 1st
Compositions as described in Section. 3. The basic inorganic alkali metal compound or the basic inorganic alkaline earth metal compound is a group consisting of oxides, hydroxides, sulfides, silicates, phosphate borates, and carbonates of alkali metals or alkaline earth metals. A composition according to claim 1 or 2, characterized in that it is selected from: 4 Basic inorganic alkaline earth metal compound is Mg
The composition according to claim 3, characterized in that (OH) ₂ . 5 The basic inorganic alkaline earth metal compound is Ca
The composition according to claim 3, characterized in that (OH) ₂ . 6. The composition of claim 1, wherein the zinc mercaptoester is zinc bis(isooctylthioglycolate) and the basic inorganic alkaline earth metal compound is Ca(OH) ₂ . 7 The zinc mercaptoester is zinc bis(isooctylthioglycolate), the basic inorganic alkaline earth metal compound is Ca(OH) ₂ , and the substituted dihydropyridine has the formula The composition according to claim 2, which has the following. 8. A claim characterized in that the composition contains 15 to 85% by weight of zinc mercaptoester and 15 to 85% by weight of a basic inorganic alkali metal compound or a basic inorganic alkaline earth metal compound, based on the total weight of the composition. The composition according to item 1. 9. Composition according to claim 2, characterized in that it contains from 1 to 50% by weight of substituted dihydropyridine, based on the total weight of the composition.