DE953996C - Polyvinyl acetate and plasticizers derived from glycols - Google Patents

Description

ISSUED DECEMBER 13, 1956

INTERNAT. CLASS C 09 j -

A 21486 IVa / 22 i

have been named as inventors

The invention relates to polyvinyl acetate adhesives - with improved adhesion through the addition of a special glycol-based plasticizer.

The new polyvinyl acetate adhesives possess permanent adhesion, and your emulsions will adhere very quickly if they are thin Layer to be applied.

It is known that polymerized vinyl esters are excellent adhesives. In particular polyvinyl acetate was widely used in the manufacture of adhesives. Such adhesives have in the joinery, in the production of layered or hard papers, in the sealing of cardboard boxes and packages in bookbinding, as tablet binders and the like found. The polyvinyl acetate used in the adhesive can be in the form of a solution in volatile solvents, in a hot melt or in an aqueous emulsion. At ao In some uses, polyvinyl acetate may be the only permanent component of the Forming adhesive, but it is more common with other adhesive masses, thickeners and especially mixed with plasticizers.

Plasticizers in polyvinyl acetate adhesives are added for the purpose of the adhesive layer to make flexible, such as B '. in the case of adhesives for bookbinding, the production of Layered papers made of foils and the like. But even then

if the flexibility of the glued product is not desired, it is often advantageous to use the Polyvinyl acetate for special purposes, e.g. B. to modify the adhesive strength of the adhesive, Incorporate plasticizers. So far, as plasticizers such. B. monoaryl or monoaralkyl ethers of glycols for polyvinyl acetate, described, which have an uninterrupted C-C chain of at least 5 and at most 10 carbon atoms. Furthermore, polyethylene glycols are used as plasticizers for polyvinyl acetate known.

It has been found that polyvinyl acetate adhesives with improved properties are obtained by using, according to the invention, polyethylene glycol ethers of a phenol or alkylphenol, in which the phenols contain no substituents other than alkyl radicals and not more than 4 alkyl carbon atoms and in which the number of oxyethylene groups in the Ether at least three times and is not greater than the expression η = iz -1,5. C, where C is the number of alkyl carbon atoms. The alkyl carbon atoms can be contained in a single straight or branched chain alkyl radical, or they can be distributed among several alkyl radicals. The polyglycol radical of the ethers used as plasticizers in the adhesives according to the invention therefore contains at least three oxyethylene groups and, in the case of unsubstituted phenyl radicals, can contain up to twelve oxyethylene groups. If the phenyl radical contains alkyl substituents, the maximum number of oxyethylene groups for each alkyl carbon atom should be reduced by 1.5 units. The proposed polyglycol ethers include 'the triethylene to dodecaethylene glycol ethers of phenol, the triethylenebis decaethylene glycol ethers of the various cresols, the triethylene to nonethylene glycol ethers of the various xylenes and ethylphenols, the triethylene and other isopropylphenols with different isopropylphenols and isopropylphenols substituted with different isopropylphenols 3 alkyl carbon atoms and the Triäthylenbis Hexaäthylenglyköläther therefore the various alkyl-substituted phenols with 4 alkylene carbon atoms.

Of the various ethers as defined above, the tetraethylene to hexaethylene glycol ethers are used of phenol and cresol · preferred as plasticizers.

The named phenolic ethers of polyglycols can be prepared by known methods. It is industrially advantageous to manufacture them in such a way that that ethylene oxide is added directly to the phenol or substituted phenol in such amounts, that the desired number of oxyethylene groups per aryl radical .aufnaht. It is known that the ethers produced in this way are mixtures of ethers. with different numbers of oxyethyl groups per mole are the average of the number of moles of ethylene oxide added per mole of phenol is equivalent to. Such mixtures are equivalent to those mentioned for the purposes of the invention individual polyglycol ethers of phenols.

These polyglycol ethers are valuable plasticizers for polyvinyl acetate adhesives in everyone of their usable forms. You can use as solutions; of polyvinyl acetate in volatile solvents be incorporated. But you can also in powdered polyvinyl acetate with formation of a product to be absorbed, which in the dry state -between two to be glued together Surfaces can be brought, and the whole thing can then be glued under heat and Pressure to be set. Furthermore, the polyvinyl acetate plasticized with the ethers described can be used be used in the hot-melt process. The plasticizers of the invention are special valuable in adhesives made from polyvinyl acetate emulsions. Such emulsions are through Emulsion polymerization of monomeric vinyl acetate obtained, taking into account the properties of the adhesive are somewhat different depending on the degree of polymerization. Suitable polyvinyl acetate emulsions are known.

The plasticizers can be added directly to the emulsions, the latter being preferred be stirred vigorously. The viscosity of the plasticized emulsions can be adjusted by adding water or regulated by the incorporation of colloidal thickeners as desired.

The ratio of plasticizer to polyvinyl acetate in the adhesive mixtures according to the invention can be very different depending on the intended use and the desired properties. Already 5 to ΐσ% plasticizer, based on the polyvinyl acetate, result in a clear, emollient effect, and these small amounts can be used with advantage in hot-melt adhesives for bookbinding purposes. If they are used in larger amounts, preferably between 20 and 150 percent by weight, based on the polyvinyl acetate content, the plasticizers according to the invention are particularly useful in emulsion adhesives because they produce a very adhesive film. Films made of polyvinyl acetate emulsions which are plasticized in this way develop a pronounced adhesive _capacity very quickly, so that the process of gluing surfaces can be greatly shortened in terms of time. Furthermore, the layers remain flexible and adhesive to an unlimited extent. So they are valuable for making adhesive tapes and strips.

It is emphasized that the loading n ₅ ferred upper amount of 150% plasticizer mentioned above is not the upper limit of the usable plasticizer content and that, based for special purposes adhesive of polyvinyl acetate, 200 ⁰ / o or more of the phenolic polyglycol ethers described above to the polyvinyl acetate, are useful and fall within the scope of the invention.

The progress achieved in terms of adhesive strength with polyvinyl acetate adhesives compared with the well-known with polyglycols and polyglycol

AEtherm prepared as plasticizers: adhesives exhibit the following comparative test results: At each ίσο Gewichtsteikn a Polyvmylacetatemulsion having a solids content of 55% (commercially available under the designation Elvacet, 8i-900 available) -were with vigorous stirring, 33.5 parts by weight of a 66 ^{_2/3 of} Given aqueous solution of the plasticizer in question. After the addition had ended, the mixture was stirred for a further V2 hour. The emulsions obtained were then allowed to age for 6 days and then ¹ coated in 0.038 mm (wet) thick films on glass plates. The films were exposed to a temperature of 25 ° and a relative humidity of 50 ° / o and their bond strength was examined after 1, 2, 20 and 58 days. The test was carried out with an Atlas Tack test apparatus, which is described in detail in US Pat. No. 2,406,989. In the investigation, a 6.45 square centimeter aluminum foil was pushed for 10 seconds under a weight of 450 g towards the. examining layer applied. After the weight had been removed, a counterforce was exerted on the film with the aid of a lever attached to the other side. The time required to separate film and foil was noted. In the case of non-adherent films, the separation took place immediately and in the case of moderately adherent films in a few seconds. If no separation was achieved after 20 seconds, the test was terminated and the corresponding film could be regarded as having very good adhesive properties.

The following table shows the plasticizers treated as described above and the results the adhesion test listed:

Together
settlement

Plasticizers

Days

(Adhesion
in seconds)

20th 20th 20th 20th 20th 20th 20th 0 0 0 0 0

ι tetraethylene glycol

monophenyl ether ... 20 20 20 20

2 tetraethylene glycol

monocresyl ether .... 20 20 20 20

3 triethylene glycol

(known plasticizer)

Polyethylene glycol
(known plasticizer)

The table clearly shows the considerable difference in the adhesive strength of the invention and the adhesives made with known plasticizers.

The following examples illustrate specific embodiments of the invention.

example 1

100 parts by weight of polyvinyl acetate latex with a Solids content of 55 ° / »are stirred vigorously, and 11 parts of monophenyl triethylene glycol ether

are added gradually. The obtained mixture is an excellent adhesive and possesses ■ • permanent adhesive strength when applied to the glass in a 0.0038 mm thick layer will. After the water has evaporated from the emulsion, the emulsion particles coagulate to form a transparent continuous layer.

Example 2

Instead of the triethylene glycol ether of Example 1, the monophenyl ether of dodecaethylene glycol is used used. The resulting mixture gives like that - of Example 1 continuously! adhesive Movies. The anhydrous film was slightly cloudy.

Example 3

1.00 parts by weight polyvinyl acetate latex with a solids content of 55% are stirred vigorously, and a solution of 55 parts of monophenylhexaethylene glycol ether in 45 parts of water is gradually added. The resulting mixture is a . excellent 'adhesive and has lasting adhesive power when in a thin Layer is applied. The anhydrous film is transparent.

Example4 9 »

Monophenyl tetraethylene glycol ether is on Place of the monophenylhexaethylene glycol ether used in Example 3 used. Like the mixture of Example 3, the product gives clear transparent, permanently adhesive layers.

Example

The condensation product of 6 moles of ethylene oxide with ι moles of mixed (ortho-, meta- and para) cresols were used in place of the monophenyl ether of Example 3. As was before · get a mixture with permanent adhesive power.

At game 6

100 parts by weight polyvinyl acetate latex with a solids content of 55% are stirred vigorously, and a solution of 83 parts of monocresyl tetraethylene glycol ether in 124 parts »water is gradually added. It becomes a very flexible one permanently adhesive adhesive obtained, which is transparent after drying.

Β e i s ρ i e 1 7

The condensation product of 4 moles of ethylene oxide and 1 mol of _11S para-tert-butylphenol was used in place of the monophenyl triäthylenglykoläthers of Example ι. The product obtained is an excellent adhesive has lasting adhesion and 'is transparent, after the water has evaporated from the emulsion _lao.

In the above examples, the test for bond strength was carried out using the test apparatus von Bonner and Brewster (U.S. Patent 406 989) using an aluminum foil as a test surface, which is under for 10 seconds

one. Weight of 450 g was placed on the layer to be examined. The contact area was 6.45 cm ² . The layers were considered permanently adhesive if the test on 7 day old layers was positive for 20 seconds.

Example 8

An excellent plasticized adhesive for bookbinding purposes can be made if, mani 5 ° / σ Monopheny läther des Tetraäthylengfykols processed with powdered polyvinyl acetate and the mixture · melts to it then on to apply the edge "- of the sheets to be bound".

In. the above examples exist Adhesives made only from polyvinyl acetate and plasticizers as active ingredients. In the preparation of Polyvinyl acetate adhesives often use other ingredients as well, and that with Polyvinyl acetate plasticized with the ethers according to the invention can also be mixed with these agents will. So ^ the products of Examples 1 to 7 with aqueous solutions of phenyl-formaldehyde condensation products processed into adhesives that are more water-resistant than unmodified polyvinyl acetate adhesive. The mixtures can be up to 50%. or more of the modifying Contain resin ·. Furthermore, thickeners such as. B. rubber, arabic, sodium arboxymethyl cellulose or the like, can be added to give them a higher viscosity if a paste-like consistency is desired is. Such modifications of the Grutidgemische according to the invention are within the scope of. Invention.

Claims (1)

PATENT CLAIMS: I. adhesives made from polyvinyl acetate and plasticizers derived from glycols; Dadkirch characterized that they contain a polyethylene glycol ether of a phenol as a plasticizer, the phenol containing no substituents other than alkyl! radicals and no more than 4 alkyl carbon atoms and ¹ the polyethylene glycol contains at least three oxyethylene groups, but not more of these groups than w in the Formula w = 1-2-1.5 C, where C is the number of alkyl carbon atoms. 2 '. Adhesive according to claim 1, characterized in that that they are in the form of an aqueous emulsion of polyvinyl acetate and polyethyleneglycol ether are present. 3. Adhesive according to claim 1 or 2, characterized characterized in that they are between 0.05 and 2 parts by weight of polyethylene glycol ether per ι Part contain polyvinyl acetate. 4. Adhesive according to one of the preceding Claims, characterized in that it is a polyethylene glycol ether of the plasticizer Contains phenols with four to six oxyethylene groups in the molecule. 5. Adhesive according to one of claims 1 to 3, characterized in that it contains a polyethylene glycol ¹ of phenol with three to twelve oxyethylene groups in the molecule as a plasticizer. 6. Adhesive according to one of claims 1 to 3, characterized in that it is as Plasticizer a polyethylene glycol ether of cresol with three to ten oxyethylene groups ■ contains in the molecule. 7. Adhesive according to one of claims 1 to 3, characterized in that it is as Plasticizer a polyethylene glycol ether of the cresol with four to six oxyethylene groups in the molecule. 8. Adhesive according to one of claims 2 and '4 or 7, characterized in that it 0.2 to 1.5 parts by weight of the polyglycol ether Contained per part of polyvinyl acetate. Contemplated pamphlets; Delmonte, "The Technology of Adhesives," 1947, p. 459;
German patent specification No. 855 439. © 609 529/500 5.56 (609 705 12.56)