DE2731776A1 - METHOD OF COATING GLASS SURFACES - Google Patents

Description

Process for coating glass surfaces

The coating of glass surfaces, especially glass bottles with a firmly adhering, uniform and transparent plastic layer gives these bottles when used for carbonated beverages, such as beer, Coca-Cola, mineral water, Fruit juice drinks, etc. provide extraordinary safety and extend the useful life of the returnable bottle. As a result Impact and impact, but also from heating in sunlight or other heat sources, it was in the past Explosions of unprotected bottles often occur, causing various serious physical injuries, in particular Eye injuries, caused in humans.

Some of the previously known coatings for this purpose have the disadvantage that the coating layer changes when repeated Cleaning becomes cloudy, which in the case of thermoplastic materials may result in a post-crystallization effect on the plastic is due. Such bottles visually convey a negative impression and are psychological in terms of sales undesirable. The disadvantage of thermosetting plastic coatings containing ether groups is their susceptibility to oxidation explains what leads to embrittlement of the protective layer and thus, especially in the case of returnable bottles, after some time Splinter protection no longer guaranteed.

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809885/0065

ORIGINAL INSPECTED

It has now been found that glass surfaces can also be coated without these and other disadvantages if one uses the method for coating, in particular glass bottles, to prevent the scattering of glass particles when bursting, with a transparent, thermosetting protective layer of more than 50 microns by applying masses of polyisocyanates and compounds containing hydroxyl groups as well as customary processing additives and curing of the coating at elevated temperatures is carried out in such a way that the clean glass surface is first treated with an aqueous or alcoholic silane size, then dried and then the glass surface treated in this way with a mass of aliphatic and / or cycloaliphatic diisocyanates or their reaction products with water in a molar ratio of 2: = 1 and a trifunctional, hydroxyl-containing polyester with an average molecular weight of 300-1400, preferably 500-800, from W hydroxycarboxylic acids or their lactones coated with at least k carbon atoms and hardened.

According to a further embodiment, up to 90% of the trifunctional, hydroxyl-containing polyester by bifunctional ones with an average molecular weight of AOO - 2 000, preferably 500 - 1 200, replace the same structure,

The protective plastic layer applied in this way is highly elastic and shows excellent adhesion, so that if the glass breaks or the bottle bursts, the glass splinters remain within the protective layer. After the destruction the glass bottle retains its shape completely. The kinetic energy that occurs is due to stretching and Heating of the plastic coating implemented.

809885/0065

- IT'S-

The resistance of the coating to hot, alkaline rinsing solutions, in which the bottles are in, is of particular advantage be cleaned before the drinks are filled. This is particularly true for returnable bottles that are available before be subjected to intensive cleaning with each filling process.

The advantage of the coating according to the invention is that, even after repeated rinsing in the hot, alkaline washing liquor, there is no loss of mechanical characteristics and no loss of adhesion. Glass bottles provided with such a plastic coating can be used without hesitation as a container for carbonated beverages, since there is no longer any danger for people if they break or burst.

When used as a returnable bottle, the useful life is a coated bottle is much longer than that of the coated bottle Bottle, which as a result of the movements caused by cross-linging on sharp edges and rinsing processes in The surfaces of hot solutions are subject to severe stress or can be easily damaged.

To carry out this process, the cleaned glass surface, for example a glass bottle, is first treated with an aqueous or alcoholic silane size. For this treatment, silanes with residues that can be assigned to two different functional groups are used. These are, on the one lower alkoxy, especially methoxy and Äthoxyreste, which react with the OH groups of the glass surface and the other organic radicals having such functional groups which can react with the isocyanate groups, such as amino _f epoxy, mercapto groups, etc. e.g. y-aminopropyl-trimethoxysilane, glycidyloxypropyl-triethoxy-silane, y-mercaptopropyi-

809885/0065

trimethoxy-silane, γ-mercaptopropyl-triethoxy-silane, etc. The treatment of the glass surface can take place, for example, by dipping or spraying with the sizing agent. The bottles treated in this way can either be ^{dried separately at 2i> 0} ° C.-100 ° C. or drying is carried out by heating the glass bottle to 80 ^° C.-100 ^° C., ie to a temperature that occurs in the course of the cooling process during bottle manufacture .

The application of the solvent-free as described below PUR two-component coating masses on the pre-fused, preheated glass! ”tabs are made according to known methods, such as Pouring, spraying, dipping, etc.

The supply of heat can after the application of the coating materials to be continued until the reaction is complete, if the existing heat capacity for curing itself is not should be heard.

The thus-coated glass bottle is then the actual curing at a temperature in the range of 150 - preferably from 2 ^ 0 ⁰ C, 100 - subjected 2IO ⁰ C.

Aliphatic and / or eye-loa-liphatic diisocyanates, such as those described, for example, in the article by W. Siefken in Justus Liebigs Annaien der Chemie 562 , pages 75-136, such as 1,2-ethylene diisocyanate and 1-tetramethylene diisocyanate, are suitable for producing the coating _t h, hexamethylene diisocyanate-1,6, 2,2, ^ - or 2,4, ^ - trimethyl-hexauiethylenedÜ3ocyanat-1,6 (TMDI), dodecane diisocyanate-1,12, Q , o) '-dilsocyanatodipropylether, lysine diisocyanate, Cyclobutane-1,3-diisocyanate, cyclohexane-1, J and -1,4-diisocyanate, 3-Isocyana tome thy L-;), '>,!> TrimethylcycLohexylisocyanat, which is also called isophorone diisocyanate and is abbreviated ^{as Ii 1 DI} , Decahydro-8-

809885/0065

ORIGINAL INSPECTED

methyl (1,4-methanoaphthalen-2 (or 3) 5-ylenediniethylene diisocyanate, decahydro - ^^ - methano-indan-i (od <r 2) 5 (or 6) ylenedimethylene diisocyanate, hexahydro - ^^ - methanindan-i - (or 2) 5 (or 6) -ylene diisocyanate, hexahydrotoluylene diisocyanate, perhydro-2,4 ¹ - and / or - ^, A'-diphenylitiethane diisocyanate and any mixtures of the isomers. Further suitable isocyanates are given in the mentioned article in the Annalen on page 122 f .. Of course, mixtures of the isocyanates can also be used.The reaction products of these diisocyanates with water in a ratio of 2: = 1 are also suitable, in particular that in DT-OS 23 41 OC ^ described.

The polyester is reacted with the diisocyanate in such amounts that for 1 OH group 0.0-1.2, preferably; 0.95-1.1 isocyanate groups come.

Trifunctional, hydroxyl-containing polyesters made from Oü -hydroxycarboxylic acid are particularly suitable for producing the solvent-free PUR two-component coatings! or their lactones, tri-functional polyesters being understood as meaning those with 3 OH groups. The molecular weight of the polyester should be in the specified range. The hydroxycarboxylic acid or its lactones have at least k carbon atoms in the chain. Those with 7 carbon atoms can be used as the upper limit. Typical examples of suitable lactones are: jf-butyrolactone, c £ -valerolactone, ^, -caprolactone, methyl- £, -caprolactone and the like,

The preparation of these lactone polyester polyols can be carried out in a known manner according to one of the US Patents 2,890,208, 2,977,885 or 2.933.478 processes described take place in which one triols as initiator with the lactones with heating with or without Catalyst converts. Suitable triols are, for example

8098 & 5 / 006S

ORIGINAL INSPECTED

Glycerine, trimethylol propane, trimethylol ethane, triethan laminate and others. Instead of the lactones, the hydroxyl-containing polyesters which can be used according to the invention can also be prepared ^{from the corresponding w -hydroxycarboxylic acids and triols by known processes.}

According to the invention, up to 9OGewj6 of the trifunctional Polyesters can also be replaced by bifunctional ones, i.e. those with 2 OH groups. These can also be configured according to the mentioned US patents described processes are prepared. In this case, diols are used as initiators used, such as ethylene glycol, neopentyl glycol, propylene glycol-1,2 and -1,3, butanediol-1,4 and -1,3 hexanediol-1,6, diethylene glycol, Triethylene glycol, etc.

According to the invention, mixtures of the tri- and bifunctional investigated polyester containing hydroxyl groups, the mixing ratio between 90:10 and 10:90, preferably 80:20 to 40:60. These figures are percentages by weight.

The reaction between polyisocyanate and polyester containing hydroxyl groups can be set in motion or accelerated by catalysts will. The following are suitable: metal organic compounds, such as tin and zinc octoate, di-n-butyltin dilaurate, di-n-butyltin diacetate etc..

To improve the leveling properties of the coatings So-called leveling agents added during preparation. These agents can include chemical compounds or whose mixtures are of different chemical nature, e.g. polymer or monomeric compounds, e.g. acetals, ethers, Copolymers of n-butyl acrylate and vinyl isobutyl ether,

809885/0066

Silicone resins, fluorinated alkyl esters, etc. Such leveling agents can be added to the formulations in amounts of 0.05-0.5% by weight. be added based on the total batch.

The coating compound can also contain customary additives, such as dyes, stabilizers and defoamers which are soluble in the polyols etc. included. These can, based on the binding agent - poly oil, Isocyanate - fluctuate within a wide range · The amount depends on the requirements for the quality of the coatings.

Before the application of the coating materials, the components A and B are intimately mixed and evacuated until no more bubbles rise. If necessary, the mixing and degassing process must be carried out carried out at an elevated temperature depending on the viscosity will.

The layer thicknesses of the cured coatings can depend on Stress on the glass surface or glass bottles between 50 and 250 pn vary.

The invention also relates to the glasses coated according to the method described above, in particular glass bottles.

The mechanical characteristics of PUR bottle coatings mentioned in the examples were determined by the following methods:

Tensile strength Ί elongation Γ according to DIN 53 455

<r ₁₀₀ voltage J

809885/0065

In addition, test films were subjected to the following stability tests subject to:

Wash liquor test: 4% by weight NaOH, 0.4% by weight Na glyconate

1 cycle: 30 minutes / 80 ⁰ C

Tropical test: 70 ⁰ C / 100 % rel. LF sterilization: 121 ° C / 2h

Furthermore, adhesion and splinter protection were tested. The splinter protection was tested in a so-called drop test. To this Purpose was in a coated 0.7 1 beverage bottle 6.3 g

HpSO, (98% strength by weight) and 9 g of NaHCO-. given and locked.

ο The resulting amount of CO ^ generates an internal pressure of approx. 4.0 atmospheres at 25 C. The test bottle prepared in this way was dropped onto a concrete slab at a height of 1.2 m and the scattering of the glass splinters was observed.

Description of the ingredients used in the examples: 1_. Component A: (hydroxyl-containing polyester)

As polyvalent; polyesters containing hydroxyl groups were the polycaprolactones from Union Carbide used and the bifunctional 1Len types based on diethylene glycol and 6 -CaprolacLon.

Polyester A: with the hydroxyl addition of 212 mg cow / g, an acid number of 0.3 mg KOH / 'g and an average molecular weight of

809885/0065

ORIGINAL INSPECTED

Polyester A ^: with a hydroxyl number of 135 mg KOH / & an acid number of 0.3 mg KOH / g and an average molecular weight of

and the trifunctional type based on 1,1,1-trimethylo propane and ε-caprolactone

Polyester A .: with a hydroxyl number of 310 mg KOH / g an acid number of 0.3 mg KOH / g and an average molecular weight of 540.

The average molecular weights of these polyesters were calculated from the hydroxyl number determined.

In addition to the monomeric isophorone diisocyanate (hardener B ^) were two urea adducts dissolved in isophorone diisocyanate, the manufactured in accordance with DT-OS 23 41 065 from IPDI and water were used, and between that

IPDI adduct B ₂ : with an NCO content of 28.7 wt. ^,

an equivalent weight of 146.3 and a viscosity at 25 ⁰ C of 6100 cP

IPDI adduct B ^: with an NCO content of 31.5 wt.} *

an equivalent weight of 133.3 and a viscosity at 25 ° C of 450 cP.

In each of the examples below, component A, consisting of the tri- and / or bifunctional, was initially used

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ORIGINAL INSPECTED

Polyester, catalyst and leveling agent are homogenized at AO - 50 ⁰ C on the dissolver and then evacuated until no more bubbles rose. Then component B - the hardener - was added, mixed and again evacuated until there were no bubbles. The coating material was applied first on untreated, to 80 - 100 ⁰ C to produce pre-heated glass sheets to films for determination of the mechanical characteristics and for the stability tests such as Waschlaugen- and tropical test as well as sterilization. For adhesion tests and drop test were pretreated with silane sizing, to 80 to 100 ⁰ C preheated glass plates and bottles coated.

Table 1 shows examples of mechanical characteristics of polyol combinations in connection with IPDI, IPDI-Add. B ₂ and B ₃ . The OH / NCO ratio was 1: 1. The curing was carried out by 15-minutiges heating at 200 ^0C

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809885/0065

Table 1:

IPDI B ₁ 1 2 3 4th 5 36.0 6th 7th 8th 9 10 11 IPDI adduct B ₂ 140 IPDI adduct B ₃ 516.38 464.49 482.39 462.2 417.5 433.81 I.
405.48 367.93 361.68 346.03 326.1 Mechanical characteristics 129.09 116.12 120.60 198.1 178.9 185.92 270.32 245.28 254.46 346.03 326.1 Tensile strength N / mm ² 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Examples Elongation % 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Component A Polyester A, 351.53 336.7 321.2 304.94 Polyester A ₂ 416.39 400.6 383.79 Sn octoate 394.01 [ 379.17 362.76 344.8 «! Commercial ver
solvent based
^ (of alkyl esters per-
oojfluorinated carbon
tnisic acids
■ ν. I. r-j component B 32.0 39 38 30.5 35 24 32 28 16.5 19.5 cn 190 100 140 210 170 26o 180 200 270 230

The results of the stability tests - wash liquor, tropical test, sterilization - are summarized in Table 3. The adhesion of the coating compositions on pretreated GIa ^ bottles and. plates (even after 5 cycles of the wash liquor test) was excellent. The splinter protection was guaranteed in the formulations with an elongation of approx.> 150 %. The lower the expansion of the films (see also comparative examples), the lower the splinter protection, ie the splinters of the bursting glass bottles can be found within a radius of> 2 m. The same observation was made when the elongation is> 150%, but the tensile strength was approximately <28 N / mm.

Table 2 shows some examples of mechanical characteristics of other polyester combinations in connection with IPDI, IPDI adduct B ₀ and B ,. The OH / NCO ratio was 1: 1. The hardening took place at 200 ^° C. within 15 minutes.

809885/0085

Table 2:

ο co OO OO

cn ο O CD Vt

example 12th 13th 14th 15th 16 17th 18th 19th 20th 21 22nd Component A Polyester A, 506.4 453.87 471.94 448.6 402.9S I 418.48 389.38 350.6 364.68 328.63 307.68 Polyester A ₁ 126.6 117.99 192.3 172.71 179.35 259.58 233.73 243.12 328.63 307.68 Sn octoate 2, o 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 commercially available
Leveling agent on
Based on alkyl
esters perfluorinated
ter carboxylic acids 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Component B IPDI 364 356.1 348.04 339.74 IPDI adduct B ₂ 429.67 421.3 412.6 ' IPDI adduct B ₂ 407.07 399.17 391.1 381.64 Mechanical characteristics data Tensile strength N / cun ² 35.0 42.5 42, c 31.5 40.5 39.0 25.5 36.0 35.0 22nd 24.5 strain % 170 65 12C 190 120 160 220 150 180 2O 215

cn

The results of the stability tests - wash liquor, tropical test, sterilization - are summarized in Table 3. The adhesion of the coating compositions to pretreated glass bottles and plates (even after a 5-cycle wash liquor test) was excellent. The splinter protection was guaranteed in the formulations with an elongation of approx. > 150 %. The lower the expansion of the film (see also comparative examples), the lower the splinter protection, ie the splinters of the bursting glass bottles can be found within a radius of> 2 m. The same observation was made when the elongation is> 150 % , but the tensile strength was approximately <28 N / mm ² .

Table 3 shows the wash liquor, tropic and sterilization resistance selected examples from Tables 1 and 2.

809885/0065

Table 3:

example K / mm ²
N / mm ² 1 4th 6th 26th 8th 190 14.5 12th 15th 17th 20th Wash runf ^{ft ntest} K / mrn ² 31.5
185
14.5 30th
205
14th 34.5
170
16 215 31.0
185
15.5 155 35
180
16 32.5
190
14.5 38.5
165
19th 34.0
185
i
15.0 80988! before tensile strength 6 * _E
^iem elongation Z _B
test
<3 " ₁₀₀ -voltage ^ ₁₀₀ 24 ■ 24.5 ^s 26 25th \
6.9 5.5 27 21.5 26th 26th Vl
O
cn
σι after the 5th cycle N / mm ² 26th 27 26.5 15, c 28 24 29 26.5 y iem C β _{u # n #} 24h at RT 190 185 195 200 170 190 X'est 150 170 135 160 150 135 140 ^ B u.n. 24h at RT 5 · 5 5 6.5 5.0 7.5 6.0 -j n. 5. Cycle 15.0 14.5 15.5 14.0 19th 14th ^ ¹⁰⁰ and 24 h at RT

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809885/0065

ORIGINAL INSPECTED

Component A

384.87 parts by weight Polyether polyol based on ethylene oxide

(OH-Z .: 108 mg KOII / g) linear

102.68 parts by weight Polyether polyol based on ethylene oxide

(OH-Z .: 258 rag KOH / g) linear

102.0 parts by weight Trimethylolpropane 2.0 parts by weight Sn octoate 1.0 part by weight Leveling agent analogous to Examples 1-22

Component B 407.45 parts by weight IPDI

Mechanical «properties

Tensile strength 18.0 N / mm ² elongation 10 %

No splinter protection guaranteed.

Comparative Example 2 Component A

225.12 parts by weight Polytetramethylene ether glycol (OH-Z .: 173.5 mg KOH / g) 262.43 parts by weight Polytetramethylene ether glycol (OH-Z .: 11U, 5 mg KOH / g) 102.0 parts by weight Trimethylol propane

2.0 parts by weight Sn octoate 1.0 part by weight Leveling agent analogous to comparison example 1

Component B 407.45 parts by weight IPDI

809885/0065

Mechanical properties

Tensile strength 35.0 N / mm elongation 160 %

Slightly scattering glass fragments were observed in the drop test. In addition, the films showed a clear after the curing process Yellow discoloration and already after a 100 h of brief weathering in the xenotest, embrittlement occurred and after 65O h total destruction of the film occurred.

dr.kn/mü.

809885/0065

Claims (1)

Patent claims 1_. Process for coating glass surfaces, in particular ^y glass bottles, to prevent the scattering of glass particles upon bursting, with a transparent, duroplastic protective layer of more than 50 microns by coating compositions comprising hydroxyl-containing compounds polyisocyanates and as well as the usual processing additives and hardening of the coating at elevated temperatures, characterized in that the pure glass surface is first treated with an aqueous or alcoholic silane size, then dried and then the glass surface treated in this way with a mass of aliphatic and / or cycloaliphatic diisocyanates or their reaction products with water in a molar ratio of 2: ^ 1 and a trifunctional part, Hydroxyl group-containing polyester with an average molecular weight of 300-1400 from oj -hydroxycarboxylic acids or their lactones coated with at least 4 carbon atoms and hardened. 2. The method according to claim 1, characterized in that that the trifunctional, hydroxyl-containing Polyester has an average molecular weight of 500-800. 809885/0065 ORIGINAL INSPECTED £. Method according to claim 1, characterized draws that up to 90% by weight of the trifunctional, hydroxyl-containing polyester, replaced by bifunctional ones with an average molecular weight of 400 - 2000. 4. The method according to claim 3, characterized shows that the bifunctional, hydroxyl-containing polyester has an average molecular weight of 500 - 1200 has. 5_. Method according to claims 1-4, characterized characterized in that polyester and polyisocyanates are used in such amounts that on one OH group 0.8-1.2 isocyanate groups come. (j. The method according to claim 5, characterized shows that there are 0.95-1.1 isocyanate groups for every OH group. 2. The method according to claims 1-6, characterized characterized in that the coated glass bottles are subjected to curing ^{at a temperature in the range from 150-240 0 C.} 8. The method according to claim 7, characterized in that the curing at temperatures in the range of 180 - 210 ⁰ C is carried out. 2 · Coated glass bottles with a transparent, thermoset Protective layer, produced according to one of claims 1 - ü. 809885/0065