DE2326998B2 - USE OF CONTACT ADHESIVES BASED ON POLYURETHANE TO BOND POLYVINYL CHLORIDE TO ITSELF OR TO OTHER MATERIALS - Google Patents

Description

3 °

It is known to use so-called solvent adhesives in the increasingly important bonding of materials of all kinds. Elastomers such as polychloroprene, butadiene-styrene copolymers, Butadicn-acrylonitrile rubber (hereinafter referred to as nitrile rubber hereinafter), polyurethane, butyl or natural rubber are the basic components of the adhesive combinations. In the processing of the ^ ₀ Polyurethane adhesives, however, arise as a result In the absence of a sufficiently long "open time", considerable difficulties. "Open time" defines the period of time after the adhesive has been applied, within which a good, non-positive connection of the parts to be _{bonded is still possible with light pressure ^ 5.} The "open time" as well as the adhesive strength in the cold and heat of adhesive systems that are not based on nitrile and polyurethane rubber can be varied within wide limits by using suitable natural or synthetic resins or adapted to the respective purpose. In particular, an improvement in the application properties, as is possible to a considerable extent in the case of contact adhesives based on polychloroprene through the use of suitable resins, has so far only been achieved to a small extent with polyurethane adhesives.

Adhesives based primarily on linear polyurethane ( ₎ have been used for a long time to bond plastics containing plasticizers with difficult adhesion conditions, such as soft PVC. In contrast to other contact adhesives, they have excellent resistance (, ₅ against a large number of common plastic softeners and against vegetable and mineral oils and fats.

The reaction of polyvalent isocyanates with hydroxyl-containing, higher molecular weight polyesters Polyurethanes are formed with resins such as those commonly used in the adhesives industry such as terpene phenolic resins, alkyl phenolic resins !! and colophony derivatives, wo! compatible, effect however, no extension of the contact tack time. After releasing the solvent, which is often very takes place quickly, and the drying of the polyurethane adhesives that takes place with it is not a contact tack more available. So mostly a heat activation, i. H. an action of heat on the solvent-free, dry adhesive film introduced into the working process with which the adhesive coated Make parts to be joined as a result of melting and renewed tackiness of the film permit.

Attempts have also been made to improve their chemical properties by adding polyurethane adhesives of polyisocyanates and to process them as two-component systems. Notes on addition of resins to increase the tackiness of such combinations are not in the publications has been mentioned. In order to achieve optimal bond strengths, heat activation must also be used here be taken. The processing of these adhesives is therefore very limited in their universality and cannot be done generally. Although it is stated that the polyurethane adhesive opposite the previous soft PVC adhesives would have a longer "open time", so that larger areas would also be available Bonding could be carried out, but this information is not specified so that the expert to this day still only undertake such bonds with great effort can.

It is also known to produce adhesives based on polyurethanes and novolaks, in which certain solvent systems are used that do not adversely affect the aging of the Effect adhesive. The adhesives are used to harden the novolaks, hexamethylenetetramine as a methylol group donor admitted. These adhesives are vulcanizing systems in which the Novolak-hexamethylenetetramine mixture takes on the role of a reinforcing additive. The storage stability the presence of hexamethylenetetramine significantly reduces the adhesive. At higher At storage temperatures, the adhesive may gel as a result of further condensation.

Also the separation strength of the resin-polyurethane mixtures modified with hexamethylenetetramine are significantly inferior to those obtained using the unmodified mixtures will.

It has now surprisingly been found that these disadvantages can be avoided and solvent-based adhesives with improved adhesion and cohesion to plasticized PVC and extended, through the "open time" of marked contact tack is obtained when using a solvent-based adhesive used, the from A) linear polyurethane and in amounts of 2 to 100% by weight, based on au A), B) Nuvüiaken from aldehydes and bisphenols Alkylphenols with at least 3 carbon atoms in the alkyl rest, arylphenols, mixtures thereof or mixtures of one or more of these phenols with up to zi 50 mol% phenol and / or alkylphenols with up to zi

2 carbon atoms as an alkyl radical or C) epoxy resins, which are formed by reacting with alcoholates of polyvalent metals are modified or D) halogenate elastomers, chlorinated polypropylene or copolymers of vinyl chloride with vinyl acetate or E) hybrids of which consists.

In addition to the stated advantages, the bonds produced with the combinations have increased Heat resistance, d. H. an increased resistance of the glue joint to the effects of warmth. When testing the shear strength, there are cracks in the material. The one usually used for gluing The required contact pressure can be used when using the solvent adhesives according to the invention be narrowed.

The linear lines used to manufacture the adhesives Polyurethanes are addition products of aromatic diisocyanates with those polyesters with terminal ends Hydroxyl groups, which are esterification products of dicarboxylic acids with diols. It deals z. B. to polyesters crosslinked with isocyanates.

The solvent adhesives used according to the invention have, based on their content of polyurethane component, 2 to 100, preferably 10 to 70% by weight of the additives or mixtures thereof.

It has also been found that, contrary to the previous view, certain phenolic resins can actually bring about a substantial increase in the contact tack time. For the production of the phenolic resins used, for. B. as aldehydes acetaldehyde, butyraldehyde, isobutyraldehyde, chloral and preferably formaldehyde, as alkylphenols z. B. p-tert-butylphenol, p-amylphenol, p-isooctylphenol, 0- and p-nonylphenol, dodecylphenol, p-cyclohexylphenol, also o- and p-phenylpheno) _v cumylphenol and those phenols that are produced by the reaction of olefinically unsaturated hydrocarbons such as, the various vinyl toluenes, terpenes such as a- undjß-pinene, cyclopentadiene and its oligomers with phenols, in particular phenol are obtained styrene a-methyl styrene turpentine; are also suitable, for. B. phenols such as diphenylolethane, diphenylolbutane, diphenylolisobutane and preferably diphenylolpropane or mixtures of one or more of the aforementioned phenols with phenol, cresols and / or xylenols. Subsequent substitution of novolaks obtained from phenols and / or bisphenols is also possible by reaction with the aforementioned hydrocarbons in the presence of protic and / or Lewis acids. If alkylphenols are used, the alkyl radical is usually in the p-position. It expediently contains up to 12 carbon atoms. The term alkyl is intended to include cycloalkyl. Often there are novolaks made of formaldehyde and bisphenols and mixed novolaks made of formaldehyde with phenols and bisphenols on the one hand and alkylphenols with at least 3 carbon atoms in the alkyl radical or arylphenols or mixtures thereof on the other hand, or substituted novolaks that are obtained by subsequent core alkylation of phenol novolaks and formaldehyde with the aforesaid unsaturated hydrocarbons.

The modified epoxy resins are prepared in a known manner from diphenylolpropane and epichlorohydrin produced epoxy resins with a) alkoxy salts, formed from the copper, cobalt or Magnesium salts of aluminum tetrabutoxyalkoxo-

acid, or with b) alcoholates of polyvalent metals such as iron (III), titanium, preferably aluminum z. B. of alcohols with 2 to 6 carbon atoms such as ethyl, propyl, butyl, amyl and hexyl alcohol and their Isomers and the monoalkyl ethers of ethane, propane and butanediol, the ether group depending on white 1 to 4 carbon atoms, expediently aluminum butoxide, or reacted with c) lead hexanate in an amount of 0.5-10, preferably 1-6, parts by weight.

Furthermore, halogen, e.g. B. Bromine or chlorine containing elastomers such as chlorinated natural rubber, chlorinated polypropylene and polymerization resins such as copolymers of vinyl chloride with vinyl acetate in a weight ratio of 1: (0.1-0.5), preferably 1: (0.15-0.3) as additives be used.

The additives used are odorless and tasteless and usually do not cause any discoloration the glue line. They can be used both on their own and in mixtures with one another in the adhesives used according to the invention are used. They are compatible with the polyurethane elastomers and do not reduce the plasticizer resistance of the adhesives.

Phenolic resins of the resol type often also cause an increase in the contact tack time, however, unpleasant odors and often discoloration of the adhesive film are often associated with an application opposite.

Preferred solvents are ketones such as acetone, methyl ethyl ketone, esters such as ethyl esters, and also chlorinated hydrocarbons and aromatic hydrocarbons. They are mainly used as mixtures and can be varied according to technical aspects.

The usual application methods for the adhesives, such as brushes, squeegees, spraying, and the Further processing of the parts provided with adhesive must be carried out when using the adhesives according to the invention cannot be changed, but can be longer due to the increased contact time Waiting time to be worked. This adhesive combination makes the gluing process more efficient, because the previously required heat source for heat activation is not required - albeit Nothing stands in the way of their additional application and, on the other hand, more economical because through the Incorrect gluing can be avoided for a longer period of time. The heat resistance can also be short-term Flashing off at 90 C can be improved.

The adhesive mixtures used according to the invention improve the possibilities of gluing PVC to a considerable extent. The PVC can be used both with itself and with other materials such as synthetic leather based on polyurethane, Rubber, leather, metal, textiles, cellulose-containing materials such as wood, paper and cardboard can be bonded.

The adhesive mixtures used according to the invention have a very good solvent, Water, oil and grease resistance as well as high adhesive strength when exposed to heat. Additions of polyisocyanates do not adversely affect these properties.

The amounts and percentages given below relate to weight. T means Part.

- ι

25 to 50 T of the additives specified above and

Manufacture of Resins 100 T * £ ™ g ^ _{yen C} h.orubber and der-

A) 457 T diphenylolpropane, 150 T toluene, 180 T ^ ^ the tables below relate

aqueous formaldehyde (30%) and 9 stsubstanzen T oxalic y _e.

are cooked for 5 hours on the back nut. Then ₅ aui _{nents were} well assimilated with agitation

azeotrope 168 T water and the rest of the toluene _{an- £ ■> Ripen solids} content of 20

finally sealed under normal pressure. According to Ernischl ^ _{% with a viscosity of} «*. 1500 cP

rich a bottom temperature of 180X w the ^"w ·, _weitcren experiments was the separation

the solvent residues during an emstund ^ en ° ^ei - _{jt investigation} , which with those, η the examples 1

Vacuum distillation removed. You get 474 T ^ of a, o ™ ^e _{used Polvurethan} en, reinforced by Tr, -

light yellow novolakes with a melting point of "^ y ^^^^^ X-triisocyanate, was obtained (Be, -

1 ^16C · .. ^ _n -T- -: _ ", i scnovnn games 13 to 15).

_{B) 456 parts of diphenylolpropane, 400 parts of} a solution of games, 3 to 1 ^^, _{was sold} , sweet poly-280T 0,0-dimethylol-p-nonylphenol in 15C "T \ y 'oil, with different strengths various e-95 T aqueous formaldehyde (30%), 50 T xylene and, ₅ ^ ^iny '^ _hmacherg ehalt used. In Prulungs-2 6T phosphoric acid are added with stirring about J ^e "" ^h ^ _x ^ ™ Unge the KlebstoITe were boiled for 3-5 hours at reflux. Then, distilled st "Ien vo _up wear and after one different at circulated until no more water deposited by ^ ¹ _ _{zuf PROVISIO} ng the contact ', and the xylene was distilled off until a sump ¹ ^ JJ. ^^ _ _tO sammengelegt and 10 seconds temp of 180 ⁰ C. to unlearn ₂₀ ^^^ T _eat . _Nac h AHeder different residual solvent is water-jet vacuum Toggle "JJ ^ t ₆ Twurden the bonds on a set of _Λ ^ ■ H nPriifcereich suitable tensile tester at a

There are 720 tons of a solid novolak, which is always g ^ g _{m / M} ^ ^ ^^ ^ ^

Has a melting point of 107 ° C. J ' ⁰ _{at room} . _and increased temperature _S e-

C) 100 T one in a known manner from 1 mole p, p -D, - 2, les ig

phenylolpropane and 2 moles of 1,3-dichlorohydrin _were tested with a terpene phenol resin

made epoxy resin are at 8 (TC with 3 T Alum, - for ^Ve ^ _{of 120} _ ₁₃ 0> C and an acid

niumbutyiat stirred and the combination to a ^ ^m ^ J ^^ calibration example 1) and a strong base

50% solution dissolved in toluene. «Active alkylphenol resin with a melting point

³⁰ before, 65-7 ° C (comparative example 2) used (see.

Part 1 and 2) which instead of the

B ice ρ ie 1 e (s. Table) '^' _{β using} t _s adhesives known additives

_are sorted 25 to 50T of the aforementioned products and ^a B ^"set ^ g _s ^e _{e ⁿ de} n tables zusammenge-

20% solutions of chlorinated rubber with 62 to ₃₅ 66/0 U "e arg _{was the} experimental rich fi.r

Chlorine content, chlorinated polypropylene with 65 to 68/0 contains · J «ventilation added at 90 ⁰ C,

Chlorine content, a polyvinyl chloride-polyvinyl acetate- the " ^h " ~ | _{that with the} according to the invention

Copolymer with a mixing ratio of around n * J ^hzu * ^el «' _{f even with} evaporation at 90 ⁰ C

about 1: 0.20 in toluene, were produced with a predominantly _{reversible advantage}

linear polyurethane, consisting of a mixture ₄ o ke ne ££ » ^ _{results of} storage stability

from polyester containing hydroxyl groups - from alipna- m «ao. _h listed, to whom

table dicarboxylic acid and diols, and aromatic ^ ^ fS ^ methylenetetramine have been added

Diisocyanates to adhesives with the following structure f ^ g ^ Den show with the addition of this substance

processed: (Examples 1-12): · _pinwöcR i _g er storage at 50 ⁰ C significant decrease

Table 1

Separation strength (kp / cm) ^ ₃ " ₆ hl"

Flash-off time 20 '^^ ^^ _{2 () χ}

Ventilation temperature » _{7 days 7 days c}

Age of bond 7 days 7 lay ^^ ^^ ^

Test temperature ^to ^

Example polyurethane with novolak *) ^ _ ^

1) + 25% resin A ⁵ '' ^ ₉ ^ ^

2) ₊ 50% resin A "_ _2J

3) + 25% resin B *> _'65 ^ ₅

4) + 50% resin B '' '

Polyurethane with modified epoxy resin **)

5) ₊ 25% resin C 6.2 7 1 6 5 - ^ ₆ ^ + 50% resin C ¹ ^

-ortset / ιιημ Polyurethane with halogen-containing polymers 6.5 4.6 - - 2.5 icigame or mixed polymers *) 7.7 7.8 7.6 - 3.3 + 25% chlorinated rubber 6.2 6.1 - - 2.6 7) + 50% chlorinated rubber 7.8 7.9 5.8 - 3.7 8th) "chlorinated polypropylene 6.0 6.1 5.9 - 2.7 9) + 50% j 7.4 7.6 7.5 7.5 3.9 10) + 25% | Copolymer of PVC N) + 50% | and polyvinyl acetate 12)

20 ' 50 ° 20 ' 1" 10 ' 20'C 0.6 20'C 20 C 9OC 20 ' 0.6 7 days 3 days 3 days 20 ° 0.7 20 ° 50 ° 20 ° 50 ° 20 ° 50 ° 2.2 8.8 _M 1.1 9.0 _M 1.8 9.2 _M 1.9 4.0 8.7 _M 1.3 8.5 µ 1.3 9.3 _M 2.3 2.4 8.7 _M 1.1 8.3 _M 1.1 8.9 _M 1.5

Comparative example c to 1 to 12

Polyurethane

without March or addition _____

+ 50% resin Comp.Example 1 _____

+ 50% resin compare example 2 _____

+ 50% resin + 3.5% hexamethylenetetramine 5.1 2.8

(based on elastomer) Comparative example 3

*) Bonding of toilet PVC with 40% plasticizer, 2 mm thick.
* ♦) Bonding of PVC floor covering with 10% plasticizer.

- No gluing possible, Klcbcillm completely dry.

Table 2

Shear strength (kp / cnr)

Bonding of soft PVC with 40% plasticizer, 2 mm thick

Flash-off time Flash-off temperature Age of the bond

Test temperature example of polyurethane

4) + 50% resin B

10) + 50% chlorinated polypropylene

12) + 50% mixed polymer of PVC and polyvinyl acetate

Comparative examples

without resin ______ _{8> 8m ] 2}

+ 50% resin, see example 1

+ 50% resin Comp. Example 2 - -

M = crack in material.

- = No gluing possible, adhesive film completely dry.

Table 3

Separation strength (kp / cm)

After reinforcement with 5%, based on the solvent mixture, of a 20% solution of triphenyl

methane 4,4 ', 4 "-triisocyanate in methyl chloride

Bonding of PVC flooring with 10% plasticizer

Ventilation rate Ventilation temperature Age of the bond

Example polyurethane

13) + 50% resin B

14) + 50% chlorine. Poly prop.

15) + 50% mix. PVC + PVAC *) without resin

- <= No gluing possible, adhesive tape completely dry. *) Polyvinyl acetate.

20 ' l ^h 20 C 3 " 6 ^h Topfzi 20 C 20 C 7 days 20'C 20'C 7 days 7 days 7 days 7 days 7.1 7.2 7.3 7.0 approx. 3 days 8.7 8.0 7.0 4.0 approx. 3 days 7.0 6.3 6.0 6.2 approx. 3 days 3.5 - - - about 3 days

9 ^

Table 4

Storage of adhesive mixtures

Storage time 7 days at 50 ° C

Polyurethane

16) + 50% resin A homogeneous

17) + 50% resin B homogeneous

Comparative examples

+ 50% resin A + 3.5% hexamethylenetetramine deposited

(based on elastomer) Comparative Example 4

+ 50% resin B + 3.5% hexamethylenetetramine deposited

(based on elastomer) Comparative Example 5

Claims (3)

Patent claims: 1. Use of solvent adhesives, consisting of A) and linear polyurethane, in quantities from 2 to 100% by weight, based on A), B) novolaks; Aldehydes and bisphenols, Alkylphenols with at least 3 carbon atoms in the alkyl radical, arylphenols, mixtures thereof or Mixtures of one or more of these phenols with up to 50 mol% of phenol and / or alkylphenols with up to 2 carbon atoms as an alkyl radical or C) epoxy resins, which by reaction with Polyvalent metal alcoholates are modified, or D) halogenated elastomers, chlorinated Polypropylene or copolymers of vinyl chloride with vinyl acetate or E) mixtures thereof for gluing polyvinyl chloride to itself or to other materials, 2. Use according to claim 1, wherein the polyurethane elastomer is based on with isocyanates is pre-crosslinked, higher molecular weight polyester containing hydroxyl groups. 3. Use of solvent adhesives according to claim 1 or 2, characterized in that that as a solvent a mixture based on ketones, esters and aromatic hydrocarbons is used. 25th