NL8101249A - PERMISSIBLE PLASTIC SHEETS, METHOD OF MANUFACTURING THE SAME, VARIOUS PAINT AND THEIR USE THEREOF. - Google Patents

Description

f -ι- το 1752

Permeable bars of plastic plates, method of manufacturing them »lacquers testing for this and their application.

The invention relates to light-permeable plastic sheets with a lacquer coating, a method of manufacturing the same, a lacquer for producing the lacquer coating as well as the use of this lacquer for protecting permeable plastic sheets against yellowing and / or embrittlement.

Translucent plastic sheets are used in large quantities in many areas of technology in everyday life. Particularly important are plastic sheets based on polyvinyl chloride (PTC), polycarbonate (? C), styrene-butadiene-10 polymers (S3) and acrylonitrile-butadiene-styrene copolymers (ABS;

The plastic sheets can be curved or curved. They can also be in the form of ball grouts or of other shapes, such as are used for example for light couplers. Particular preference is given to plastic plates that are multi-walled, in particular double-walled, the walls being connected to each other by connecting pieces. Such so-called hollow core profiles have the extraordinary advantage that they are highly insulating. All such known embodiments of plastic plates are included within the concept of plastic plates in the scope of the invention. Preferably £ 0 have plastic sheets according to the invention made from the above-mentioned plastics. The manufacture thereof usually takes place by extrusion.

It is known that such plastic sheets resp. utensils and a lacquer coating can be protected against certain effects, making them eg scratch resistant or spring and light resistant. In German Offenlegungsschrift No. 2,607,923, a lacquer coating based on polyisocyanate and epoxy resins has been proposed in this connection. However, this does not provide sufficient resistance to the body.

The most disadvantageous for transparent plastics have the special drawback that their properties deteriorate with long-term irradiation with sunlight. Many plastics have a particularly high degree of bonding, e.g. with PTC. With other plastics, on the other hand, embrittlement cp, e.g.

- 'Λ * o /, c -2- r ♦ · for PC, SB and IBS.

The object of the invention is now to provide transparent plastic plates with a high spring resistance against the action of sunlight. According to the invention, transparent plastic sheets are plastic sheets which are permeable to sunlight. They have a special technical significance as coverings for greenhouses, light flares in industrial halls, sports halls, riding halls, swimming pools, balcony and terrace coverings, exhibition pavilions, etc.

It has now been surprisingly found that more transparent plastic sheets with a lacquer coating have a special resistance to sunlight when they meet the following defined structure.

The invention thus relates to light-transparent plastic sheets which are characterized in that the lacquer coating has a thickness of 5 ~ 80 µm and a) as binders polymerisates of lower alkyl acrylic acid or methacrylic acid esters, b) as ITV absorbers 2 ~ (2- hydrowy-3,5-dialkyl-aryl) -2H-benzriazoles in an amount of 0.5 to 10% by weight, based on the lacquer film, c) quenching agents in an amount of 0.5-10. wt #, based on the lacquer film.

The plastic sheets according to the invention are preferably colorless. However, they may also have a weak tint when this is necessary for certain purposes.

The lacquer coating advantageously has a thickness of at least 10 µm, preferably at least 20 µm, and at most 60 µm, preferably at most + 0 µm. It is further expedient that the lacquer coating 30 contain at least an amount of 1.0 wt.%, Preferably at least 1.5 wt.% And at most 8.0 wt.%, Preferably it contains at most 5 wt.% UV absorber ". Moreover, it is expedient for the lacquer coating to extinguish the extinguishing agent in an amount of at least 1.0% by weight, preferably 1.5% by weight, and at most 8.0% by weight, preferably at most wt. # ".

It is advantageous to use the UV absorber and quencher in an amount of about 1: 1. The fraction of these components in the lacquer may be the smaller, the thicker the applied lacquer film.

It is expedient that the lacquer coating contains as a binder polyalkyl methacrylate, preferably polymethyl imethacrylate.

The essential characteristic of the binder is that it has a high compatibility or compatibility with the transparent plastic plates to be lacquered, that is to say, it binds well, even after extremely long irradiation with sunlight. It is particularly surprising that the transparent plastic sheets according to the invention do not exhibit inferior properties in fibers, even if they are exposed to strong sunlight for more than 5 years, respectively. exposed to the spring.

The binders themselves exhibit a special resistance to sunlight or. weather resistance, i.e. no cracks forming. The binder must be readily soluble in the solvents used. It should furthermore be particularly compatible with applied UV absorbers and quenching agents, i.e. they must not crystallize or migrate from the binder film even after a longer period of time.

The UY-abs orptants used according to the invention are known per se (sterically hindered amines}. The 2- (2-hydroxy-3,5-di-tert-amyl-phenyl) -2E-benzrizole is, for example, the commercial product Tinuvin 328 from Firma Ciba-Geigy, Switzerland.

Quenching agents used according to the invention are also products known per se. The product di- (1,2,2,6,6-25-pentyl-1-k-piperiol) -2-1-butyl-1-2 (3,5-di-tert-butyl-U-hydroxy-bensyl) - maleate is the commercial product Tinuvin lUt from Ciba-Geigy, Switzerland.

According to the invention, on the one hand excellent protection is achieved on the one hand by a relatively thin lacquer coating due to the aforementioned defined concentrations of 30 µV absorbents and extinguishing agents, while on the other hand reducing the protection due to the above-mentioned disturbances, e.g. crystallization; avoided. The protection of the transparent plastic is achieved by the lacquer coating according to the invention to a degree which has hitherto not been considered possible, as have been the case with long-term tests.

According to the invention, light-transparent plastic sheets are particularly preferred, which are characterized in that the plastic is flat and consists of PVC, ABS or SB, and the lacquer coating as a binder OH-functional polyaerylate resins and / or OH -Functional phthalic acid polyesters in combination with aliphatic polyisocyanates.

In the lacquer solutions used according to the invention, the OH-functional resins gradually react with the polyisocyanates.

This has such an effect that the viscosity gradually increases. As a rule, it is possible for the lacquer solutions to be processed effortlessly and flawlessly up to 36 hours after preparation. After application, drying first takes place, in particular because the solvents evaporate. The drying crack with which a dust-free surface is reached as quickly as possible can thereby be accelerated that the lacquer solutions contain cellulose ethers and / or esters or half esters, preferably cellulose acetobutyrate. The addition of these compounds to the lacquer solutions is known per se (compare eg British Patent Specification 1,28 + 755). The cellulose acetobutyrate contains a small fraction of OH groups. As a result, the cellulose acetobutyrate also reacts with the isocyanate groups and can thus be incorporated into the resin system during curing.

The binders added according to the invention have the special advantage that the mechanical resistance of the coatings obtained is particularly great. Abrasion resistance to abrasive influences is excellent. Irrespective of the high hardness which the coatings according to the invention have, they have a surprisingly high impact toughness or impact resistance, in particular at very low temperatures, eg down to minus 20 ° C. The lacquer coatings of the plastic sheets according to the invention thus have the mutually exclusive properties of a high hardness and a simultaneous high impact toughness.

A further advantage of the lacquer coatings of the plastic sheets according to the invention is that the solvent resistance is very high. Reversible dissolution of the cured lacquer coatings with conventional solvents is generally not possible.

The subject of the invention is furthermore a process for the manufacture of the above-mentioned light-transparent plastic plates, characterized in that a solution of 81012 4 9 -5- a) 15- ^ 0 of polymers of lower alkyl acrylates is applied to the plastic plates. - or methacrylic acid esters, or for PVC, ABS or SB plastic sheets with 15 to 60 wt. / 5 OH-functional polyacrylate resins and / or OH-functional phosphoric acid polyesters in combination with aliphatic polyisocyanates, 5 b} 0,1-¾ % by weight of 2- (2-hydroxy-3,5-dialkyl-aryl) -2H-benzrizazoles, c) 0.1-% by weight of quenching agents, d) in low boiling solvents with a flash point below about bO ° C in an amount of 10A00 g / m. and the solvents evaporate at temperatures of up to 60 ° C object temperature.

Preferably, the solution is applied in an amount of at least 20 g / m 2, preferably at least 10 g / m and at most 300 g / m, preferably at most 200 g / m.

It is preferred that the solution contain the UV absorbers in an amount of at least 0.2 wt%, preferably at least 0.3 wt% and at most 3.2 wt%, preferably 2.0 wt%. contains.

It is further preferred that the solution be the quenching agents in an amount of at least 0.2 wt%, preferably at least 0.3 wt% and at most 3.2 wt%, preferably 2, Contains 0 wt. $. PClyalkyl methacrylates, preferably polynethyl methacrylates, are suitably used as binders.

Special examples for suitable solvents are aromatics such as toluene, xylene; esters, such as methyl acetate, ethyl acetate, butyl acetate, methyl glycol acetate, ethyl glycol acetate, and mixtures thereof.

The drying times should be as short as possible. According to the invention, drying times of up to ^ minutes, preferably up to 30 minutes, are achieved. As a rule, sufficient drying has already been achieved after 15 minutes, preferably after about 20 minutes. After this period of time, the painted surface becomes dust dry. However, stack elasticity is not reached until after 12 to 15 hours. All drying times refer to drying under normal conditions (23 ° C, 55.¾ relative humidity). The binders used are known per se. Particularly suitable are, for example, OH-functional polyacrylates from Synres, Holland, which are available in the nannex under the name Synedol. Other particularly suitable binders according to the invention are the polyacrylates described in DE-AS 2.021.178 with or without styrene contents. Styrene-free polyacrylates are preferred. These are commercial products of the firm AG with the trade names Macrynal.

Suitable OH-functional phthalic acid polyesters are the esters which are commercially available under the name Desmophen from Bayer, Leverkusen.

The OH-functional polyacrylates and / or polyesters are used in combination with commercially available aliphatic polyisocyanates, such as are commercially available, for example, under the name Desmodur from Bayer, Leverkusen. Especially preferred are polyisocyanates based on hexamethylene diisocyanate. Preference is given to an OH content of about 3-10, preferably about k-Q wt.% In the polyesters, and in the polyacrylates about 0.5-3, preferably 1-2% by weight.

The aforementioned binders are particularly suitable for lacquers to be applied to PVC, ABS or SB plastic films.

For all transparent plastic films, lacquers are particularly suitable, which contain polymethyl methacrylates as binders. Particularly suitable are, for example, a polymethyl methacrylate from Rohm and Haas, which is commercially available under the designation Paraloid B kk. Another particularly suitable binding agent according to the invention is a binding agent built up on the same plastic basis, which is commercially available from Poly-Vinylehemie, Holland under the designation Neocryl B 723.

Suitable lacquer additives for the lacquers are silicone oils to improve scratch resistance and defoaming agents effective in casting such lacquers. In most cases, drying is sufficient after about 8 or 5 minutes.

The solvents used according to the invention have excellent solubility for the binders used. On the one hand, they only dissolve the plastics very little, respectively. only very slight swelling of the plastic sheets when applying the lacquer solution. They also process very fast drying. By adhering to the above-defined maximum drying temperature, adverse effects on the properties of 8101 2 4 9 -7. avoid the plastic plates. The correct temperature, which may be used to the maximum during drying, can easily be determined in special cases. The production of the transparent plastic sheets with a lacquer coating according to the invention expediently takes place immediately after the manufacture of the plastic sheets in series production. In the case of uniform plastic plates, the lacquer coating is applied in an effective manner by means of a casting method.In this way, a particularly uniform coating can be ensured.However, however, other coating methods customary in the field of lacquering can be used, which produce an even lacquer coating.

The invention is further directed to a UV protection lacquer containing binders, solvents, UV absorbers and extinguishing agents, as well as any usual paint additives, characterized in that they a) 15-1 * 0 gsw.% Polymers of lower alkyl acrylic acids or -ethacrylic acid esters, or for the manufacture of light-transparent plastic sheets of PVC, ABS or SB 15-60% by weight of OH-functional polyacrylate resins and / or OH-functional phthalic acid polyesters in combination with 20 aliphatic polyisccyanates, b } 0.1-wt.% Yes 2- (2-hydroxy-3,5-di-alkylaryl) -2K-benztriazoles, c) 0.1-wt. quenching agents, d) 52-87% by weight of low boiling point solvents with a flash point below

about hQ C.

25 contains.

The invention is furthermore directed to the use of the aforementioned lacquers to protect light-transparent plastic sheets against yellowing and / or becoming brittle.

The invention is now explained with reference to the drawing tce-30. In the individual figures, like parts are designated with like reference numerals. Figure 1 shows a schematic section through a simple light-transparent plastic sheet according to the invention. The plastic sheet itself is indicated by 1 and the paint coating by 2. Figure 2 represents a schematic cross-section through a plastic sheet according to the invention, which is double-walled, the walls being connected to each other by connecting pieces. Both walls were designated 1a and 1b. They are connected by the 3101249 -8 pieces 3. The lacquer layer 2 is applied to the top walls 1a,

Example I

On the later outer surface of a double-walled light-wall PVC profile, a lacquer with the following composition is applied by casting.

26 g of polymethyl methacrylate (commercial product Paraloid B bra from the company

Rohm and Haas) 0.8 g of UV absorber (Tinuvin 328 commercial product from Ciba-Geigy, Switzerland).

0.8 g of quencher (commercial product Tinuvin 1UU from Urma Ciba-Geigy) 0.2 g of silicone oil (commercial product Baysilon 02 from Bayer AG).

0.2 g defoamer, 21 g toluene, 31 g ethyl acetate 20 g ethanol in an amount of 90 g / m 2, which after drying at 23 ° C gives a dry film thickness of 22 µm.

The light-walled profile thus coated showed no yellowing even after 100 hours of irradiation with UV-light (250-UOO nm), in contrast to the uncoated profiles of the same type, which had yellowed considerably after this treatment.

Example II

A flat sheet of ABS plastic of 3 mm layer thickness' 25. was spray coated on one side with lacquer of the following composition: 20 g polymethyl methacrylate 1.0 g UV absorber (Tinuvin 328) 1.0 µg quencher (Tinuvin ibb) 30 i +0 g ethyl acetate 12 g toluene 26 g ethanol.

The film thickness of the dry film was 25 µm. The flat sheet thus coated did not show corrosion after irradiation, as described in Example I, 35, while the untreated sheet subsequently became very brittle.

81 01 2 4 9 ......

Yooroeeld III

-9-

A light-transparent plastic sheet of pcb carbonate, as described in Example II, provided with a lacquer layer. The same result as in Example II is obtained.

Example IV

On the later outer surface of a PVC double-walled heat-profile, a lacquer EAT was applied to the following composition in an amount of 88 g / m, which after drying at 23 ° C gave a thickness of the dry film of 22 µm.

10 20.0 g styrene-free OH-functional polyacrylate resin 3.0 g cellulose acetobutyrate 7 ', 0 g aliphatic polyisocyanate Besmodur N 0.1 g organofunctional silicone oil as lubricant 0.8 g U7 absorbent 2- (2-hydroxy-3,5-di- tert .asy-1-phenyl) -2H-15 benztriazcol 0.8 g quench dl- (1,2,2,6,6-pentylmethyl-piperidyl} -2-li-butyl-2 (3.5 di-tert.-butyl-hydrozybenzyl) maloneate h2, Q g ethyl glycol acetate 10.0 g xylene 20 16.3 g toluene 100.0 g

The light-walled profile thus coated showed no yellowing after 100 hours of irradiation with 50 µm (250 µm), unlike the uncoated profiles of the same type, which had yellowed considerably after this treatment.

Example V

A flat sheet of ABS plastic with a thickness of 3 m was coated on one side by spraying a lacquer with the following coating systems: 30 7.0 g GH-functional phthalic acid polyester with 8% w / 0H groups

20.0 g OH-furikthlonal phthalic acid polyesters with 0.3% by weight OH groups, g g alxfatx polyisocyanate as in Example I

0.1 g of silicone oil as in Example I 1 »3 g of UY absorption Expansion seals in Example I.

* W X. 1.0 e 1.0 g of agent as in Example I.

27.3 g ethyl glycol acetate 01 01 2 4 9 -10- ♦ 8.0 g "butyl acetate 10.0 g xylene 100.0 g 2

The amount applied was 5 5 g / m and the thickness of the dry film was about 22 u m. The flat sheet thus coated showed no embrittlement after irradiation, as described in Example 1, whereas the untreated flat sheet had become very brittle.

8101249 _

Claims (10)

1. Light-transmitting plastics sheet with a lacquer coating, characterized in that the lacquer coating has a thickness of Tan 5-80 µm and 5 a) polymers as binders. Language lower alkyl acrylic or methacrylic esters, t) as UY absorbers 2- (2 -hydroxy-3,5-dialkylacryl) -2H-benzria sols in a Tan 0.5-10% by weight, based on the lacquer film, c) quenching agents in a Tan 0.5-10% by weight. %, based on the 10 lacquer film. 2. Plastic sheets According to claim 1, characterized in that the lacquer coating has a thickness of Tan at least 10, at least 20 and at most 60, at Toorkeur not more than U0 ym. Plastic sheets According to claim 1 or 2, characterized in that the lacquer coating contains the UV absorber hSTat in a quantity of Tan at least 1.0, at least 1.5, and at most 8.0, at most 5 wt. . $. h. Plastic sheets According to claims 1-3, characterized in that the lacquer coating has the coating agents in a proportion of Tan at least 1.0, preferably at least 1.5 and at most 8.0, at preference 5.0. f beTat. Plastic sheets According to claims 1-3, characterized in that the lacquer coating contains polyalkyl methacrylates, preferably polynethylnethacrylates, as binders. 6. Plastic plates According to claims 1-4, characterized in that the plastic plates consist of PVC, ABS or SB, and the lacquer coating as a binder OE-functional polyacrylate resin and / or OH-functional phthalic acid polyesters in combination with aliphatic polyisocyanates . T. Method for Manufacturing Tan light-transparent plastic sheets According to claim 1, characterized in that the plastic sheets are a solution of Tan a 15-4-0% by weight of polymers of Tan lower alkyl acrylic acid or methacrylic acid esters, or PVC, ABS or SB Tan 15-Ö0 plastic sheet 5 CH-FUT-rit xonsle polyacrylate resin and / or 0H-functional phthalic-polyesters xn combination with aliphatic polyisccyanates, b) 0.1-4 felt 5 2- ( 2-hydroxy-3,5-dialkyiaryl) -2H-benzotriazGlen, 811249--12- e) 0.1-1 + wt. Extinguishing agents, d) in low-boiling solvents with a flash point below about 1 + 0 ° C, in an amount of 10-1 + 00 g / m is lifted and the solvent is evaporated at temperatures of up to 60 ° C object temperature. Method according to claim 7, characterized in that the solution is applied in an amount of at least 20, preferably at least 1 + 0 and at most 300, preferably at most 200 g / m. 9. Method according to claim 7 or 8, characterized in that the solution contains the UV absorber in an amount of at least Q, 2, preferably at least 0.3 and at most 3.2, preferably 2.0% by weight. he barrel. 10. Process according to claims 7 to 9, characterized in that the solution comprises the quenching agent in an amount of at least 0.2, preferably at least 0.3 and at most 3.2, preferably 2.0% by weight. . 11. Process according to claims 7-10, characterized in that the solution comprises as a binder polyalkyl methacrylate, it preferably comprises polymethyl methacrylate. 12. UY-protection lacquer containing binder, solvent, UV absorber and extinguishing agent as well as any usual lacquer additives, characterized in that these a) 15-wt.% Polymers of lower alkyl-acrylic or methacrylic acid esters, or for the production of light-transparent plastic sheets from PVC, ABS or SB 15-60% by weight of 0H-functional polyacrylate resins and / or 0H-functional phthalic polyesters in combination with aliphatic polyisocyanates, b) 0.1-h wt% 2- ( 2-hydroxy-3,5-dialkyl-aryl) -2H-benztriazoles, 30 c) 0.1-1 + wt.% Quenching agents, d) 52-87 wt.% Low boiling solvents with a flash point below about 1 + 0 ° C hates. 13. Use of a lacquer according to claim 12 for protecting light-transparent plastic sheets against yellowing and / or hrosing. 8101240 .........