EP1761595A1

EP1761595A1 - Method for stabilizing polyvinyl chloride that is antimicrobially equipped with zinc pyrithione

Info

Publication number: EP1761595A1
Application number: EP05752656A
Authority: EP
Inventors: Andrea-Louis Noseda; Peter Stutte
Original assignee: Sanitized AG
Current assignee: Sanitized AG
Priority date: 2004-06-16
Filing date: 2005-05-24
Publication date: 2007-03-14
Also published as: WO2005123818A1

Abstract

A method for stabilizing polyvinyl chloride and PVC processing materials, wherein antimicrobial equipping is provided by adding zinc pyrithione, and optionally other active substances. Discolouration of the PVC material caused by the zinc pyrithione is counteracted by adding a thermo and light protection stabilizer system, consisting of the same or different organic and/or metal-organic stabilizer types, in addition to technically conventional stabilization. Stabilized zinc-pyrithione compositions for antimicrobially equipping products containing PVC are also disclosed. .

Description

Process for stabilizing polyvinyl chloride with antimicrobial treatment with zinc pyrithione

The present invention relates to the field of plastics, in particular polyvinyl chloride plastics, and relates to a process for the thermal and light stabilization of polyvinyl chloride processing compositions which are antimicrobially equipped and thermally processed by adding zinc pyrithione and optionally other active ingredients, and in which the addition of zinc pyrithione leads to an impairment of the stability properties, according to the preamble of claim 1. Furthermore, the invention relates to antimicrobial compositions for use in polyvinyl chloride plastics according to the preamble of the second independent claim.

The processing materials mentioned are primarily piastisoles and PVC hot mixtures; However, the invention can be applied to all compositions which consist entirely or partly of polyvinyl chloride, are processed warm and are antimicrobially treated with at least zinc pyrithione.

Polyvinyl chloride is a thermoplastic that has been known for a long time. It is used for many applications, including - and in particular - for the production of floor and wall coverings, tarpaulins,

Roof coverings, awnings, tents, synthetic leather, swimming pool foils, bath mats,

Seals, conveyor belts, cable jackets and many other items.

A large part of the polyvinyl chloride (PVC) used today is processed as so-called plastisol and hot mix. As is known to the person skilled in the art, plastisols are dispersions of thermoplastic PVC in plasticizers, in particular esters of phthalic acid with aliphatic alcohols, for example dibutyl phthalate, diisononyl phthalate, di- (2-ethylhexyl) phthalate etc., which are easily deformable at room temperature because they are be in a liquid state. The plastisol is poured onto a solid support. When heated to about 160 to 200 ° C, depending on Composition, gels the plastisol by forming a homogeneous mixture from the original dispersion, which has the properties of a melt; gelling can also begin at lower temperatures, for example from about 100 ° C. When cooling, the melt solidifies to a solid which, depending on the intended use, remains on the carrier mentioned or is pulled off from it. Another important form of processing are the so-called hot mixes, which are mainly produced in heating-cooling mixers and processed on kneaders, screw machines, calenders, etc. The manufacture and application of objects made from

Polyvinyl chloride to be produced by heating, in particular from plastisols and PVC hot mixtures, requires the addition of one or more stabilizers. The stabilizer (s) are intended to ensure thermal stability during the processing of the PVC masses, i.e. prevent decomposition, yellowing etc. and they should furthermore have a favorable effect on the transparency, color retention, brilliance, light fastness and light resistance to normal and ultraviolet light and, if appropriate, other important manufacturing and use properties of the polyvinyl chloride product.

The most important classes of stabilizers are metal soaps, for example barium, zinc and calcium salts of especially higher ones

Fatty acids, in particular stearic acid, including their mixtures and mixed salts, also called metal soaps; Farther

Organotin compounds, e.g. aliphatic tin mercaptides or

Thioic acid salts such as octyltin mercaptide and dioctyltin thiopropionate, as well as a whole series of other compounds, including aromatic compounds such as zinc butylbenzoate, dibenzoylmethane, bariumdimethylethylbenzoate,

Metal salt complexes of nonylphenol and phosphorus-containing compounds and many others. Other stabilizer examples are in particular

Barium / zinc stabilizers, calcium / zinc stabilizers, barium / cadmium stabilizers, lead stabilizers or metal-free stabilizers and

Mixtures of those with or without additional components. This

Stabilizers are manufactured and used individually or as mixtures. Furthermore, a PVC processing composition often contains fillers and / or pigments because such additives also reduce abrasion and increase the hardness of the product. In addition, additives to improve the tensile strength may also be present, for example organic or inorganic fibers. Lubricants are often added for improved processability.

Further information on soft PVC, plastisols and stabilizers as well as other auxiliaries can be found in the technical publications of the manufacturers of PVC and stabilizers. Efforts are being made to keep the concentration of stabilizers as low as possible, on the one hand for economic reasons, since the stabilizers are much more expensive than PVC and plasticizers, and on the other hand for technical reasons. In addition to the intended properties, additives to plastisols as well as to other PVC materials always show side effects in the products, i.e. they undesirably influence other, desired properties of the product. The concentration of stabilizers in PVC products, to which no special requirements are made during and after processing and which are intended for use under normal environmental conditions, generally does not exceed the value of 1.5 phr (per 100 parts of resin, ie PVC), whereby concentrations of around 0.7 phr are sufficient in many cases.

In addition, it has proven necessary to provide the products obtained from PVC, in particular soft PVC, with an antimicrobial treatment. Up until a few years ago, diphenoxarsin-10-yl oxide and tributyltin were frequently used for this purpose. In recent years, the compound zinc bis- (2-pyridinthiol-N-oxide), referred to as zinc pyrithione or ZnPT, has proven itself in its place. This compound has a wide spectrum of activity with high effectiveness against bacteria, fungi and higher aquatic organisms. This biocide is preferably added to the PVC processing composition in a concentration of 0.05 to 0.2% by weight in order to provide it and the products made from it with a reliable antimicrobial treatment. Unfortunately, it was observed that the compound is not sufficiently heat-resistant at the processing temperatures of the PVC masses, usually 160 to 210 ° C, decomposes and causes yellowing of the PVC products even at relatively low temperatures, from around 170 ° C , leads. Proposals have already been made to protect the ZnPT from thermal decomposition by adding another stabilizer. For example, Japanese Patent Application No. 2000-029896, published on August 14, 2001 under No. 2001-220464, describes an antimicrobial formulation for high-molecular materials which, in addition to zinc pyrithione, contains a metal salt, for example zinc, a dihydroxydiphenylmethane phosphoric acid ester or the corresponding free acid ,

To solve the problem, US Pat. No. 6,525,117-B1 proposes stabilizing the zinc pyrithione by adding a mixed metal hydroxycarbonate. It is in particular a mineral known as hydrotalcite, a magnesium aluminum hydroxide carbonate, which as far as known today acts as a physical acid scavenger.

However, these known proposals have disadvantages that affect their enforcement in the art. The phosphoric acid esters of the Japanese patent application are not harmless to health and therefore represent an incalculable risk to the health of people who come into contact with the PVC products. The addition of relatively large amounts of hydrotalcite with about 1% by weight according to Example 1 of the US patent leads to the introduction of very undesirable aluminum ions into the PVC product; in addition, the hydrocalcite releases water and carbon dioxide when heated above 130 ° C., which leads to an impairment of the appearance of the finished product due to the formation of gas bubbles and very fine water droplets, ie to turbidity, and to an impairment of the strength properties. Finally, the addition of inorganic insoluble substances to products that should appear transparent is not possible, or at least critical. The object of the invention is to provide a method for antimicrobial

To create equipment for PVC products using zinc pyrithione, in which the disadvantages described no longer occur. Another object of the invention is to provide a special composition for carrying out the method.

The inventive method is in the characterizing part of

Claim 1 defined. A preferred composition for

Execution of the procedure forms the subject of the second independent

Claim. Particular or preferred embodiments are described in the dependent claims.

The invention makes use of the surprising finding that when a PVC processing composition which contains an antimicrobially effective amount of zinc pyrithione without an additional stabilizer is heated, essentially the same coloration occurs as that which occurs with an insufficient amount of heat stabilizer for the PVC Processing mass shows, and at approximately the same temperatures. According to the invention, the assumption could be based on this that the zinc pyrithione not only attacks the PVC at least at the temperatures required for the gelation of a plastisol or the heat processing of other PVC processing compositions in industrial processes, e.g. in US-6'525'117-B1, but also partially or completely renders the thermal stabilizer of the PVC ineffective, e.g. blocked. This does not necessarily involve a more or less complete, destructive decomposition of the zinc pyrithione, but it is also conceivable that the zinc pyrithione molecule splits up and each gap piece intercepts and deactivates ions or other molecular parts of the thermal PVC stabilizer (s), for example by complex formation ,

The invention provides the essential advantage that for the thermal stabilization of PVC plastisol and other PVC-containing processing compositions, which zinc pyrithione and possibly still others

Contain compounds as a biocide, no new substances or those whose side effects are not known, but that merely to increase the amount of stabilizer normally added or to add a certain amount of another suitable stabilizer.

The amount of thermal PVC stabilizer that is additionally required due to the presence of zinc pyrithione depends on the circumstances of the process, mainly also the processing temperature. At relatively low processing temperatures, for example between 150 and 170 ° C, less additional stabilizer is required than at higher temperatures. Furthermore, the amount added depends on the composition of the

Processing mass different. So far, only an insignificant dependency on the chemical composition of the heat stabilizer (s) present in the PVC preliminary product has been observed. In general, the weight ratio of zinc pyrithione to additional stabilizer is 1: 0.1 to 1:20, preferably in the range from 1: 2 to 1:12 and in most cases 1: 4 to 1: 8.

As already mentioned, the amount of stabilizer added is generally only slightly dependent on the chemical composition of the stabilizer. It is therefore not absolutely necessary to select a specific stabilizer, for example one that is not provided in the PVC formulation to be finished. However, it is readily possible to determine the stabilizer which gives particularly good results and to use it together with the zinc pyrithione. The person skilled in the art can determine this by a few simple experiments. The additional amount of stabilizer can be added before, after or simultaneously with the addition of the zinc pyrithione, but in any case before or during the thermal processing and loading. The present invention also provides compositions containing zinc pyrithione and the required amount of stabilizer. These compositions are usually in the form of a liquid, paste or powder mixture. For easier incorporation into the PVC Processing mixture, the mixture can also be stretched by adding plasticizer or plastisol, so that an easily metered, durable composition is available. A mixture of zinc pyrithione, stabilizer and plasticizer is particularly preferred, consisting of about 1 to 25% by weight of zinc pyrithione, about 1 to 95% by weight of stabilizer and the remainder to 100% by weight of plasticizer and / or auxiliaries such as, for example PVC exists.

It is preferred that such a mixture forms a finely divided dispersion in a liquid plasticizer or, together with a thickener, a stable dispersion. If PVC is used as a thickener, a plastisol is formed.

For many applications, it is preferred to adjust the grain size of the solids in this composition to a desired, usually small, value by using appropriate methods, preferably grinding using a ball mill, bead mill or

Three-roll mill.

Another preferred form of such a mixture are solid mixtures, in particular powder mixtures between the active ingredient zinc pyrithione, a powdered stabilizer, such as barium or calcium stearate, and optionally actuating and auxiliary substances.

The invention will now be explained further using examples which do not restrict it.

Example 1 :

Using a dissolver, a plastisol, hereinafter called "basic plastisol transparent", is produced with the following components:

Diisononyl phthalate plasticizer (DINP, e.g. Palatinol N,

BASF) 350 g

Polyvinyl chloride (emulsion type, K value 70; e.g. Evipol EP 7050, EVC) 650 g Ba / Zn stabilizer (Mark BZ 529, Crompton) 20 g UV stabilizer (Sandovur VSU, Clariant) 6 g

In each case 100 g of the above "basic plastisol transparent" are given an antimicrobial treatment by adding 0.1 g of zinc pyrithione to the dissolver and with varying amounts of 0 g to 0.7 g, corresponding to 0 to 7 times the amount of zinc pyrithione, of a liquid barium / Zinc stabilizer with a low zinc content additionally stabilized.

The piastisols prepared in this way are applied by means of a doctor knife in a layer thickness of 0.8 mm to release paper and gelled in an oven at 170 ° C. for 7 minutes. The effect of the zinc pyrithione and the additional stabilization on the thermal stability of the worn-out foils is determined by the fact that the time until the brownish discoloration begins when the worn-out foils are thermally stressed at 190 ° C. in a convection oven, also called "glass plate test", is determined.

The results are shown in Table 1 below.

TABLE 1

Example 2:

Experimental arrangement according to Example 1, but additionally stabilized by adding a liquid barium soap instead of the barium / zinc stabilizer.

The results are shown in Table 2 below.

TABLE 2

Example 3: Experimental arrangement according to Example 1, but additionally stabilized by adding a powdered barium stearate stabilizer instead of the liquid barium / zinc stabilizer.

The results are shown in Table 3.

Table 3

Example 4:

Using a dissolver, a plastisol, hereinafter referred to as "basic plastisol white", is produced with the following components:

Diisononyl phthalate plasticizer (DINP, e.g. Palatinol N, BASF) 330 g polyvinyl chloride (emulsion type, K value 70; e.g. Evipol EP 7050, EVC) 650 g Ca / Zn stabilizer (Bärostab CT 9156, Bärlocher) 16 g epoxidized soybean oil (ESBO) 2 g UV stabilizer (Sandovur VSU, Clariant) 6 g light stabilizer (HALS), Hostavin N24 4 g titanium dioxide (TiO ₂ ), Kronos 2220 5 g

In each case 100 g of the above "basic plastisol white" are made antimicrobial by adding 0.2 g of zinc pyrithione to the dissolver and with varying amounts of 0 g to 1.4 g, corresponding to 0 to 7 times the amount of zinc pyrithione, of a liquid barium / Zinc stabilizer with a low zinc content additionally stabilized. The plastisols prepared in this way are applied by means of a doctor blade in a layer thickness of 0.8 mm to release paper and gelled in an oven at 170 ° C. for 7 minutes.

The effect of the zinc pyrithione and the additional stabilization on the thermal stability of the worn-out foils is determined by the fact that the time until the brownish discoloration begins when the worn-out foils are thermally stressed at 190 ° C. in a convection oven, also called "glass plate test", is measured.

Table 4

Example 5:

50.5 g of diisononyl phthalate are mixed with 250 g of a liquid Ba / Zn stabilizer, here UBZ 81 bar from Bärlocher GmbH, in a double-walled chrome steel stirring vessel using a dissolver stirrer. Now 49.5 g of zinc pyrithione powder with a content of 95-100% are stirred in, mixed intensively and deagglomerated. 150 g of an emulsion polyvinyl chloride, for example Evipol EP 7050, EVC, are then mixed in with vigorous mixing and stirring is continued. The melt temperature should not exceed 35 ° C. In this form, this composition can be added to and incorporated into a wide variety of polyvinyl chloride processing compositions.

Example 6: The composition from Example 5 is wet-milled using a bead mill. The wet grinding process is controlled so that the

Grist temperature does not exceed 35 ° C.

The maximum grain size measured with the grindometer is less than 30 micrometers; the storage stability is further improved compared to the composition from Example 5.

In this form, this composition can be added to and incorporated into a wide variety of polyvinyl chloride processing compositions.

Example 7: 100.4 g of diisononyl phthalate are mixed with 200 g of a liquid Ba stabilizer, in this example Inter MOE 6504 from Bärlocher GmbH, in a double-walled stirred vessel made of chrome steel by means of a dissolver stirrer. Then 39.6 g of zinc pyrithione powder with a content of 95-100% are stirred in, mixed intensively and deagglomerated. 60 g of an emulsion polyvinyl chloride, here Evipol EP 7050, EVC, are then mixed in with vigorous mixing and stirring is continued. The melt temperature should not exceed 35 ° C.

This composition is wet milled using a pearl mill. The wet grinding process is controlled so that the ground material temperature rises to 45 ° C. The maximum grain size of this composition is less than 30 micrometers. In this form, this composition can be added to and incorporated into a wide variety of polyvinyl chloride processing compositions.

Example 8: 390.5 g of fine-grained barium stearate are in a powder mixer

(Bärostab 370, Bärlocher GmbH), 40 g of an emulsion polyvinyl chloride (Evipol EP 7050, EVC) and 49.5 g zinc pyrithione (Zink Omadine, ARCH-Chemicals) mixed. This powder mixture is adjusted to be low-dust using 20 g of a dedusting agent (Twitchell 6808 or diisononyl phthalate).

Example 9: A powder mixture is prepared according to the procedure of Example 8, the same amount being used instead of the 390.5 g of barium stearate

Calcium stearate (Ceasit I, Bärlocher GmbH) is used.

The low-dust composition obtained can be added in this form to a wide variety of polyvinyl chloride processing compositions and incorporated into them.

The usefulness of the present invention is clearly evident from the examples in that the addition of an already used or another analog stabilizer to the antimicrobial zinc pyrithione prevents a deterioration in the product qualities. Of course, the person skilled in the art will endeavor to use only the smallest amount of additional stabilizer required to "neutralize" the disruptive influence on the product, that of the zinc pyrithione is exercised to admit. The optimal amount can be determined by simple tests.

The invention can be adapted to the respective requirements in a variety of ways within the scope of the stress. For example, it is also possible to use not only one of the stabilizers already present, but a mixture of stabilizers together with the zinc pyrithione. This can lead to a synergistic effect in that a mixture of stabilizers is more effective than just one of the components, which can reduce the amount of additionally required stabilizer.

It is also possible to apply the invention not only to polyvinyl chloride plastisols, but also to other polymer mixtures which are processed in a similar manner, for example copolymers of vinyl chloride with other monomers or else to other polymer plastisols.

Claims

claims

1. A process for the thermal and light stabilization of a processing composition containing polyvinyl chloride, which is antimicrobially equipped and thermally processed by adding at least zinc pyrithione, and in which the addition of zinc pyrithione leads to an impairment of the stability properties, characterized in that this impairment of the stability properties of the processing composition is counteracted by adding a thermal and light protection stabilizer system consisting of the same or different organic and / or organometallic stabilizer types to the processing mass in addition to the technically customary stabilization.

2. The method according to claim 1, characterized in that the additional thermal and light stabilization by adding technically commonly used thermal and light stabilization systems, such as organotin stabilizers, barium soaps, calcium soaps, barium / zinc stabilizers, calcium / Zinc stabilizers, barium / cadmium stabilizers, lead stabilizers and / or metal-free stabilizers and stabilizing additives _! such as higher fatty acids - preferably stearic acid - is achieved.

3. The method according to claims 1 and 2, characterized in that the additional stabilization by adding a

Barium soap or calcium soap, or a barium / zinc stabilizer or calcium / zinc stabilizer, preferably with a low zinc content, and / or mixtures thereof.

4. The method according to any one of claims 1 to 3, characterized in that the amount of stabilizer added is 0.1 to 20 times, preferably 2 to 12 times and ideally 4 to 8 times the zinc pyrithione.

5. Composition for the antimicrobial finishing of products containing polyvinyl chloride and polyvinyl chloride with zinc pyrithione, characterized by a content of zinc pyrithione and at least one thermal and light stabilizer for polyvinyl chloride.

6. Composition according to claim 5, characterized in that the composition in addition to the zinc pyrithione one or more thermal and light stabilizers such as organotin stabilizers, barium soaps, calcium soaps, barium / zinc stabilizers, calcium / zinc stabilizers, Barium / cadmium stabilizers, lead stabilizers or metal-free stabilizers, preferably barium or calcium soaps, or respectively barium / zinc or calcium / zinc stabilizers, these preferably with a low zinc content, or mixtures of those with or without additional components such as plasticizers, preferably phthalate derivatives, and / or polymers such as PVC, and / or auxiliaries such as calcium carbonate.

7. Composition according to claim 5 or 6, characterized in that the amount of stabilizer is 0.1 to 20 times, preferably 2 to 12 times and ideally 4 to 8 times the zinc pyrithione.

8. Composition according to one of claims 5 to 7, characterized in that it contains 5 to 25% by weight of zinc pyrithione, preferably 8 to 15% by weight, and 10 to 95% by weight of a barium or calcium soap or of a barium / zinc stabilizer or calcium / zinc stabilizer, which preferably contains a small amount of zinc, but preferably 30 to 80% by weight and can additionally contain adjusting and formulating agents.

9. Composition according to one of claims 5 to 8, characterized in that the grain size of the solids contained in the composition is adjusted to the desired value by means of suitable processes, preferably by grinding using a ball mill, bead mill or three-roll mill.

10. Products made entirely or predominantly from

Polyvinyl chloride exist and have been produced by the process according to at least one of claims 1 to 4.