DE2510734A1 - METHOD OF COATING GLASS BOTTLES - Google Patents

Description

Gelsenkirclien-Buer, March 11, 1975

Veba-Chemie. Aktiengesellschaft Gelsenkirchen-Buer

Process for coating glass bottles

Bas coating glass bottles with a firmly adhering, uniform and transparent plastic layer gives this Bottles when used for carbonated beverages such as mineral water, beer, fruit juice drinks, etc., an extraordinary one Safety and extends the service life of the reusable bottle. As a result of impact and impact, but also by heating in sunlight or at sources of heat In the past, there have been frequent explosions of unprotected bottles, with variously severe physical injuries Injuries, particularly eye injuries, to humans.

Some of the previously known coatings for this purpose have the disadvantage that the coating layer with repeated Cleaning becomes cloudy, which may result in a post-crystallization effect when using thermoplastic materials of the plastic. Such bottles give a negative visual impression and are therefore undesirable in terms of sales psychology.

- 2

β 0 9 8 4 0 / ö a el ORIGINAL

It has now been found that one can also use glass bottles without them and other disadvantages with good handling properties at the same time can coat if you consider the process of coating glass bottles with a transparent, thermosetting plastic Protective layer executes so that one first cleans the glass bottles with an aqueous or alcoholic one SiIanschlicht treated, the bottles dries if necessary and then heated to a temperature of 180 - 250 C, electrostatically using the powder coating from 1,2 ~ epoxy compounds at least one epoxy group in the molecule and a lower melting point of> 40 ° C and hardeners and processing additives applies, with amidines of the general formula as hardeners

RR
I ι
RC - C- R used,

R ¹ -NN

wherein R is hydrogen, an alkyl or aryl radical, R ^{1 is} a cycloalkyl, heteroalkyl or R radical, R "is an optionally alkyl or aryl-substituted alkylene or aryl radical and X is hydrogen or a

R-C-N ^

I ^ C- remainder

RCN ^
<ι

R R '

means and, if necessary, the powder layer hardens with further supply of heat.

609840/08 68

The protective layer applied in this way is highly elastic and has excellent adhesion, so that if the glass breaks or If the bottle bursts, the splinters of glass cannot penetrate to the outside. After the destruction of the glass bottle remains keep the bottle shape fully. The kinetic energy that occurs is generated by stretching and heating the plastic coating implemented.

The resistance of the coating to hot, alkaline rinsing solutions in which the Bottles are cleaned before filling the luxury food. This is particularly true for returnable bottles that be subjected to intensive cleaning before each filling process.

The advantage of the coating according to the invention is that even after repeated rinsing in the hot, alkaline Wash liquor no softening of the material and no loss of adhesion occurs. There are also no changes in appearance.

The glass bottles coated in this way can be used as a container for carbonated beverages without risk if they break or Burst can be used.

When used as returnable bottles, the useful life of a coated bottle is much longer than that of the unprotected bottle, which as a result of the movements caused by sharp edges rubbing against each other and rinsing processes in The surface of hot alkaline solutions is heavily stressed or easily damaged.

To carry out this procedure, the cleaned glass bottle first treated with an aqueous or alcoholic silane size. For the treatment, silanes with residues are used are used, which can be assigned to two different function types.

- 4 -609840/0868

- ■ 4 -

These are firstly lower alkoxy radicals, especially methoxy and ethoxy radicals, which react with OH groups on the glass surface, and secondly, organic radicals with functional groups that can react either with the 1 ^ epoxy compounds, such as amino groups, or with the hardener, e.g. Spoxy groups, glycidyl radicals, among others, such as Y-aminopropyl-trimethoxy-silane, γ-aminopropyl-triethoxy-silane, Glycidjrloxypropyl-trimethoxysilane, glycidyloxypropyl-triethoxy-silane, etc. Mixtures with similar functional groups can also be used, ie mixtures of those reactive with epoxy groups Groups or groups that react with the hardeners. The treatment of the glass bottle can take place, for example, by dipping or spraying with the sizing agent. The bottles treated in this way can then be dried separately. The drying can simultaneously by heating the bottle at 180 - 250 ⁰ C take place, that is to a temperature wiesle in bottle production during the cooling process occurs.

The powder coatings described below are applied to the heated glass bottles using known methods, e.g., by electrostatic powder spraying; but it can also be done by vortex sintering or electrostatic vortex sintering etc. take place.

The immediate melting of the powder lying in the melting range of approx. 100 ^° C. causes the excellent, transparent flow of the film.

The supply of heat can - if the existing heat capacity is not sufficient for curing - even after the powder coating has been applied to be continued until fully networked.

The thus-coated glass bottle is subjected to curing at a temperature in the range of 140 -, preferably 180 240 ⁰ C - 200 ⁰ C subjected.

- 5 -

609840/0 8 68

"Which are for the production of fine-particle mixtures as Pulverlaeke application Bollen, 1,2-epoxy compounds are suitable with at least one 1,2-epoxide group in the molecule and a lower fusing point of> 40 ⁰ C, compounds that meet these characteristics are even polyepoxide that are solid at 40 ^° C and below, including higher molecular weight compounds (so-called solid resins), and those that are fes ⁴ "due to their symmetrical structure or the size of the carbon radicals bonded to the 1,2-epoxy group, and on the other hand, those which have been produced by the reaction of liquid 1,2-epoxy compounds with more than one epoxy group per molecule with primary or secondary amines in such an amount that the adduct still contains at least one 1,2-epoxy group per molecule on average ( so-called adduct hardeners),

The 1 _f 2-Epoxidvei'bindungen can be both saturated and unsaturated and aliphatic, cycloaliphatic, aromatic or heterocyclic. They can also contain those substituents which do not cause any disruptive side reactions under the conditions of misehing or reaction. For example, alkyl or aryl substituents, hydroxyl groups, ither groups and the like do not cause any side reactions. The suitable compounds belong to the following classes of substances: epoxides of mono- or polyunsaturated hydrocarbons, halogen-containing epoxides, epoxy ethers of single or multiple alcohols and phenols, epoxies of mono- or polybasic acids and N-containing epoxides.

Of the solid resins, 1,2-epoxy compounds are used for this purpose with more than one epoxy group in the molecule, the epoxy equivalent weight of which is between 500-1000 lies. These are, for example, the solid, polymeric ones

609640/0868

Polyglycidyl polyether of 2,2-bis- (4-hydroxyphenyl} -propane, for example by the reaction of 2,2-bis (4-hydroxyphenyl) propane with epichlorohydrin in molar ratios from 1: 1.9 to 1 * 2 (in the presence of an alkali hydroxide in the aqueous medium) can be obtained. Polymeric polyepoxides of this type can also be obtained by reacting a polyglyeidyl ether 2,2-bis- (4-hydroxyphenyl) -propane with less than the equimolecular Amount of dihydric phenol, preferably in the presence of a catalyst such as a tertiary alloy, a tertiary phosphine or a quaternary phosphonium salt. The polyepoxide can also be a solid epoxidized polyester, which is obtained, for example, by reaction a polyhydric alcohol and / or a polybasic carboxylic acid or its anhydride with a low molecular weight polyepoxide. Examples of such low molecular weight polyepoxides are the liquid diglycidyl ether of 2,2-bis- (4-hydroxyphenyl) ) propane, diglycidyl phthalate, diglycidyl tetrahydrophthalate, Diglycidyl hexahydrophthalate, diglycidyl adipate, diglycidyl maleate and the 3,4-epoxycyclohexyl methyl ester of 3 »4-epoxycyclohexanecarboxylic acid.

Mixtures of solid polyepoxides may also be used, for example a mixture of a polyepoxide, whose melting point is between 120 and 16O ° C and a polyepoxide having a melting point between 60 and 80 ⁰ C (melting point is determined by the mercury method of Durrans). Suitable mixtures contain between 30 and 50% by weight of a solid polyglycidyl ether of 2,2-bis (4-hydroxyphenyl) propane with an epoxy equivalent weight between 1650 and 2050 and a melting point of 120 to 160 ° C., and between 50 and 70 Weight of a solid polyglycidyl polyether of 2,2-bis (4-hydroxyphenyl) propane with an epoxy equivalent weight between 450 and 525 and a melting point of 60 to 80 ° C.

6098A0 / 08SB

If a high epoxy functionality appears to be desirable, a preferred polyepoxide is the polyglycidic ethers of 1,1,2,2-tetra- (4-hydroxyphenyl) -ethane.

Epoxidized polybutadienes can also be used for this purpose.

As mentioned earlier, in addition to the so-called solid resins, adduct hardeners are also suitable for carrying out the process according to the invention. Such tests of adduct hardeners can, for example, be made from liquid polyepoxides of polyunsaturated hydrocarbons, such as vinylcyclohexene, dicyclopentadiene, etc., epoxy ethers of polyhydric alcohols and phenols, etc., and aliphatic, cycloaliphatic and aromatic diamines. The prerequisite for the suitability of such an adduct is that the lower "melting point" is above 40 ^° C. here as well.

Just like the pure epoxy compounds, their mixtures, for example those of mono- and polyepoxides, be used by the process according to the invention.

Suitable cyclic amidines, i.e. imidazoline derivatives in the context of the present invention are 2-methylimidazoline, 2,4-dimethylimidazoline, 2-ethylimidazoline, 2-ethyl-4-methylimidazoline, 2-benzyl-imidazoline, 2-phenylimidazoline, 2-phenyl-4-methylimidazoline, 2- (o-tolyl) -imidazoline, 2- (p-tolyl) -imidazoline, 1,4-tetramethylene-bis-imidazoline, 1,1,3-trimethyl-1,4-tetramethylene-bis-imidazoline, 1,3,3-trimethyl-1,4-tetramethylene bis-imidazoline, 1,1,3-trimethyl-1,4-tetramethylene-bis-4-methylimidazoline, 1,3,3-trimethyl-1,4-tetramethylene-bis-4-methylimidazoline, 2- (m-pyridyl) -imidazoline, 2 ~ (p-pyridyl) -imidazoline, 1,2-phenylene-bis-imidazoline, 1,3-phenylene-bis-

- 8 - ■

609840/0868

imidazoline, 1 _f 4-phenylene-bis-irnidazoline, 1, 4-phenylene-bis-4-methylimidazoline, etc. Mixtures of these imidazoline derivatives can also be used according to the invention. Of these groups of imidazolines, 2-phenylimidazoline is preferred. These compounds can be used as sole hardeners or crosslinkers for the 1,2-epoxy compounds.

The imidazoline derivatives described above are used in amounts such that 4-12% by weight, preferably 6-8% by weight, based on the total amount of powder coating, come.

So-called leveling agents are added during preparation to improve the leveling properties of the coatings. at these agents can be chemical compounds or their mixtures of different chemical types, e.g. Polymers or monomeric compounds, acetals, v / ie polyvinyl formal, Polyvinyl acetal, polyvinyl butyral, polyvinyl acetobutyral or di-2-ethylhexyl-i-butyraldehyde acetal, di-2-ethylhexyl-n ~ butyraldehyde acetal, Diethyl-2-ethylhexanal acetal, di-n-butyl-2-ethyl-hexanal acetal, di ~ i-butyl-2 ~ ethylhexanal acetal, Di-2-ethyl-hexyl-acetaldehyde-acetal and others, ethers, such as the polymeric polyethylene and polypropylene glycols, copolymers of n-butyl acrylate and vinyl isobutyl ether, ketone-aldehyde condensation resins, solid silicone resins or mixtures of zinc soaps, fatty acids and aromatic carboxylic acids Among other things, products are also sold for this purpose,

such as Modaflow ^v , whose chemical character is unknown to consumers and which is only known to be a complex, polymeric, active liquid. Such leveling agents can be contained in the batches in amounts of 0.2-5.0% by weight , based on the total amount of the powder.

609840/0868

The other common constituents of the powder coating mixture, such as dyes soluble in the 1,2-epoxy compounds, stabilizers inter alia, based on the amount of 1,2-epoxy compound and harder vary within a wider range. It can vary according to the requirements for the quality of the coatings judge.

Before they are used, the powder coating components are intimately mixed at temperatures below the curing temperatures, extruded and then ground. For practical use, a particle size of <100 u aimed at, with the maximum particle size between 30 and 50 u should lie.

The layer thicknesses of the cured coatings can be set between 50 and 250 μm, depending on the stress on the bottles will.

General description of the methodology used

Non-tempered and pure glass bottles were initially filled with aqueous or alcoholic ^ -aminopropyl-triethoxy-silane solution (1.5 wt.? o) coated with an approximately monomolecular layer at room temperature and then dried.

The 1,2-epoxy compounds used with the special Characteristics, usually referred to as epoxy resin in practice, with the imidazoline derivatives, which act both as crosslinkers and hardeners, and the leveling agent in the specified Mixed weight ratios, extruded and then ground. The particle size of the powder components was <100 µm. The frequency distribution of the particle size possessed in the range of 30 -50 about its maximum. These fine-grained

- 10 -

609840/0868

• τ 10 -

Mixtures were then applied to the preheated glass bottles by electrostatic powder spraying and then if necessary, cured at the stated temperatures and times. The properties of the coatings obtained were subjected to the following tests.

Example 1:

2-Phenyl-imidazoline was treated with the specified epoxy resin and a small amount of leveling agent in the following ratio processed into the coating powder:

Solid epoxy resin based on an adduct of 2,2-bis- (4-hydroxyphenyl) propane (diane) and epichlorohydrin, which was subjected to HCl cleavage and then reacted with further diane, and which, according to the manufacturer, is an epoxide - Has an equivalent weight of 900 - 1000, which corresponds to an epoxy value of 0.10 - 0.11, and a melting range of 90 - 100 ⁰ CJ 93 _f 5% by weight

2-phenyl-imidazoline; 6.0 wt%

Leveling agent, which is available in stores under

the name Modaflow '* ¹ ' is available; 0.5 wt.%

This formulation was applied to glass bottles with a temperature of ^{200 ° C. and cured at 180 °} C. for 5 minutes. The following tests were carried out on the coated bottles;

a. Visual assessment: The surface showed a bare,

smooth appearance, b ^ layer thickness; 60 - 70 pm

- 11 -

6098AO / O86 &

Burst pressure

Test in the Waschmas chine

Test in the Line Simulator bottle temp eratur

80 ⁰ C!

5x1 minute running time in the line simulator

The bottles burst at an internal pressure of 22-26 atm with a fine splinter image.
The plastic jacket held the resulting splinters completely together.

The test consisted of a wash liquor .Calgonit- '* / sodium hydroxide solution (0.25 / 2.5 Gew.96) and was 5 minutes at 85 ⁰ C to the bottles allowed to act. The total time of the cycle in the washing machine was 30 minutes. The plastic did not show any negative changes afterwards,

The bottles were first ^{filled with hot water at 80 °} C. and then placed in a water bath at a temperature of 80 ^° C. for 10 minutes. The heated bottles were then tested for 1 minute in the line simulator.

After the test, there were no abrasion points in the area of the bottle body Determine plastic coating.

The test explained above was repeated five times. No damage was found.

* Calgonite

Bottle cleaning - - 12 means based on the
Sodium salt of a polyphosphate

609840/086 8

f. impact test

(Splinter cohesion): The impact test was carried out with a

Impact energy of 73 kg cm carried out. A steel ball fell of 80 mm diameter 350 mm drop height to the horizontal at a guide angle of 120 C. lying empty bottle. The bottles broke and were deformed by the blow, However, they were preserved as a whole, without any splinters of glass escaping to the outside.

According to DIN 53 373, the “puncture test with electronic Measured value acquisition "carried out. Based on his results, he left the flexibility and resistance recognize a plastic film.

The layer thicknesses of the foils were between 115 and pii. The following test settings were used:

Sample form: flat film

Machine: Dynatester

Test temperature: 24 ⁰ C

Relative humidity: 70 %

Puncture body: hemisphere

Results from 10 exams

Damage force F ₅ : 14.17 kp

Damage work W: 2.67 kgfcm

Piercing work W: 4.05 kgfcm

Damage deformation L: 5.08 mm

- 13 -

609840/0868

2B10734

~ 13 -

Example 2:

2-Phenyi-imidazoline was given with the epoxy resin as well processed with a small addition of leveling agent in the following ratio to the coating powder:

Solid epoxy resin (according to Example 1); 93.5 wt.! " 2-phenyl-imidazoline: 6.0 wt. %

Course with ttol (according to Example 1): 0.5

This formulation was applied to glass bottles, which had a temperature of about 24Q ⁰ C at the moment of order. There was no post-curing.

The tests on the coated bottles were carried out as explained in Example 1, with the results from Example 1 were obtained.

Example 5:

1,4-Tetramethylene-bis-imidszoline was given with the Epoxy resin as well as a small addition of leveling agent processed in the following ratio to the coating powder:

Solid epoxy resin (as described in Example 1): 94.0% by weight 1,4-tetra-methylene-bis-imidazoline:.. 5.5% by weight of leveling agent (according to Example 1): 0.5 Gew./o

This formulation was applied to glass bottles, which had been heated to 200 ⁰ C. No post-curing was carried out. The following tests were then carried out:

- 14 -609840/0868

a. Visual assessment

b ^ layer thickness c. Burst pressure

<i. Test in the washing machine

e. Test in the line simulator tests according to example 1e

f. impact test

(Splinter cohesion) Test according to Example 1 The surface showed a bare, smooth appearance.

70 - 80 pn

The bottles burst at an internal pressure of 20 -? 24 atu with a fine fragment image. The plastic coating held the splinters together,

The test was carried out according to Example Id.

After the specified time, there were no negative changes in the plastic here either.

The plastic coating showed only minor abrasion points. After 5x1 minute running time further damage not found.

The bottles broke and were deformed by the blow, but remained as a whole obtain.

Example 4:

2-Phenyl-4-methyl-imidazoline was made with the specified epoxy resin as well as a small addition of leveling agent in the following ratio to the coating powder:

- 15 -

609840 / 08S8

Composition_des_CoatingS2powder

Solid epoxy resin (according to Example 1): 2-phenyl-4-methyl-imidazoline:

Leveling agent (according to example 1);

94.5 wt. 56 5.0 wt. Tf 0.5 wt

This formulation "was applied to glass bottles at 200 ^° C. These coatings were then cured for 10 minutes at 200 ° C. and subjected to the following tests:

a. Visual assessment

b ^ layer thickness c. Burst pressure

Test in the Waschmas chine

Test in the Line Simulator Tests according to Example Ie : The surface showed a bare, smooth appearance.

60-80 µm

The bottles burst at an internal pressure of 20-24 atu with a fine fragment image. The plastic coating did not leave any splinters penetrate.

Test according to example 1_d. No negative changes after the trial period.

Apart from a few slight abrasion spots, the coating was completely preserved. After a running time of 5 × 1 minute, there were no further ones Injuries to the plastic layer.

- 16 -

609840/0868

d ». Impact test

(Splinter cohesion)

Test according to example V £, * The bottles broke and

were deformed by the blow, but remained as Receive the Ganges »

- 17 -

609840/0868

Claims (1)

Godparents t_a__n_s_g__r ü ^ c ^ h ^ e ^ Γ Λ J Process for coating glass bottles with a transparent, thermosetting protective layer by applying powder coatings made of 1,2-epoxy compounds with at least one 1,2-epoxy group in the molecule and a lower melting point of y 40 ⁰ C and hardeners as well as processing additives and curing the powder layer at elevated temperatures, characterized gekennzeicnnet that one first treats the clean glass bottle with an aqueous or alcoholic Silancchlichte, bottles, optionally dried and then heated to a temperature of 180 - heated 250 ⁰ C, electrostatically applying the powder coating to give as a hardener amidines of general formula RR
i I R-C-C-R used I I R'- N N R "
ι where R is hydrogen, an alkyl or aryl radical, R ^? a cycloalkyl, heterocycloalkyl or R radical, R ″ an optionally alkyl or aryl-substituted alkylene or arylene radical and X is hydrogen or R - C -
I.
C -
I. f - —Kesx go;: -... · ■ .__ R - R. R ¹ means and with optionally further supply of heat the Powder layer hardens. - 18 609840/0868 Process according to Claim 1, characterized in that the coated glass bottle is subjected to hardening at a temperature in the range from 140 to 240 ^° C, preferably from 180 to 200 ^° C. Process according to Claims 1 and 2, characterized in that the cyclic Amidine 2-phenyl-imidazoline is used. hj_ Process according to Claims 1-3, characterized in that the cyclic amidines are used in amounts of 4-12% by weight, preferably 6-8% by weight , based on the total amount of the powder coating. 5i. Method according to claims 1-4, characterized ge indicates that dyes soluble in the 1,2-epoxy compounds are added to the powder coating. 6th Process according to Claims 1-3, characterized in that the coating of the glass bottles with the powder coatings is carried out by whirl sintering or electrostatic whirl sintering. 7 * Coated glass bottle with a transparent, thermosetting protective layer, produced according to one of claims 1-6. dr.kn.-wi 609840/0868