DE3025127A1 - Cyano:acrylate adhesive contg. multi-chain ether deriv. - as catalyst, also new ortho-ester(s) of polyethylene glycol mono:ether (s) - Google Patents

Abstract

Adhesive contains (a) alpha-cyanoacrylate and (b) as polymerisation polymerisation catalyst, polyoxyethylene cpds. of formula. A(-XCH2(CH2OCH2)n-Y-R)2 (I), R1-Z-(-XCH2(CH2OCH2)n-Y-R2)3 (II) or Z-Z(-XCH2(CH2OCH2)n-Y-R)4 (III) where A is divalent atom or diatomic gp. and Z is tetravalent atom. In each cpd. branches are the same or different. R is 1-12C (substd) hydrocarbyl. R1 is H or lower alkyl and R2 is lower R'' alkyl; X and Y are gps. contg. donor atoms, or, if A is present X and Y are O, S or -N-CH3, and Y may also be -N-; and when B is present, X and Y are O; and n are integers. Cpds. of formula (II), where X and Y are O, B is Si and n are 2-50 are new and are claimed. Cpds. of formula (III), where X and Y are O, B is Si or C are also new. The catalysts can be prepd. easily in good yield and with high purity. They are used in the adhesive in low concn. and give shorter setting times on wood and other porous/acid surfaces. The adhesive has less sensitivity to water and better storage stability.

Description

Description

The invention relates to a quick-setting adhesive composition based on O ^ cyanoacrylate with good storage stability and in particular an adhesive composition, which has shorter setting times on wood and other substrates with a porous / acidic surface, than previously proposed Q ^ cyanoacrylate adhesive compositions.

O ^ -Cyanoacrylate with the general formula

CH ₂ = C ^ III

are fast-curing adhesives that are excellent for bonding a large number of materials suitable, whereby a connection of the parts to be joined can be achieved in an extremely short time of a few seconds and the bonds produced in this way have good mechanical strength values. The hardening of this Adhesives is made through anionic polymerization, which even with small traces of extremely weakly basic compounds (Lewis bases) such as water or methanol is released.

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When using such oL cyanoacrylate adhesives Wood, leather and other porous / acidic surfaces, however, have the problem that anionic polymerization of Λ, -Cyanoacrylal despite the high moisture content, which should actually promote the polymerization, is inhibited and thereby the setting time for the Adhesive is too long for practical use. In addition, such adhesives tend to penetrate the pores of the to penetrate surfaces to be bonded, so that the strength of the bonded joint with the materials mentioned deteriorated due to the prolonged setting time.

However, since the ultimate ADVANTAGES] of cL-cyanoacrylate KJebstoffen lies precisely in their short setting time, it has been attempted by various means to achieve a shortening of the setting times on wood and similar materials. This can be done, on the one hand, by treating one of the wooden surfaces to be bonded with a primer and the other with the oil-cyanoacrylate adhesive composition, whereupon the polymerization occurs when the surfaces are joined. A serious disadvantage of this process is the additional operation of applying the primer. On the other hand, the amount of acidic stabilizers added to achieve a satisfactory storage stability of the oC-cyanoacrylate adhesive compositions can be reduced.

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the. This shortened /. Was the setting time, but tend such adhesive compositions intensified at an early stage Hardening on storage.

Polymerization catalysts have therefore been proposed which are suitable for use in one-component systems and the setting times of such e> C-cyanoacrylate adhesives shorten without causing excessive deterioration in storage stability. According to the DE-OS 28 16 836 is a shortening of the setting time o £ - Cyanoacry lat adhesives achieved by the Adhesive composition about 0.1 ppm or more of a macrocyclic Polyether compound from the group of the macrocyclic Polyether and its analogs is added. The main disadvantage of these accelerators lies in their synthesis, even when using the dilution principle, the desired product is only in low yield provides, since the intermolecular link to form chains versus the intramolecular link to macrocycles is heavily favored. It is also proposed in US Pat. No. 4,170 b85, adhesive compositions based on oC-cyanoacrylates about 0.0001 to 20% by weight of a polyethylene glycol with a degree of polymerization of at least 3 and / or a non-ionic surfactant with a polyethylenoxy component (Degree of polymerization also at least 3) to be added. Disadvantageous with the compounds mentioned is the fact that this is conditioned by their

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Manufacture Contain water and low molecular weight polyethylene glycol ethers, which are difficult to remove and when introducing the compounds in et.-Cyano acryl at spontaneously initiate polymerization.

In the two cited publications are in the rest the disadvantages of oC cyanoacrylate adhesives mentioned above discussed in detail when used on wood, leather and other porous / acidic surfaces.

It has now been found, surprisingly, that the difficulties mentioned and the disadvantages of the prior art associated polymerization catalysts by using compounds as polymerization catalysts can avoid, which are easily free of polymerization-triggering substances in high yield and purity can be produced that only low concentrations in the resulting adhesive compositions based on Require oC cyanoacrylate and that also on wood and others porous / acidic surfaces lead to greatly reduced setting times.

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The invention therefore provides an adhesive composition based on «* · cyanoacrylate and usual Additions of the type identified in the claims.

The generally known oC-cyanoacrylates which form the basis of the adhesive composition according to the invention the general formula

^ CN

CH; = C III

^^ - COOR

in which R _{1 is,} for example, one of the groups mentioned in claims 8 and 9 (cf., inter alia, DE-OS 28 16 836, in which a large number of suitable oC -cyanoacrylates is mentioned). In addition, the adhesive compositions according to the invention can contain customary additives such as polymerization inhibitors, thickeners, plasticizers, perfumes, dyes, pigments and the like. Such additives belong to the state of the art and are described, for example, in the publications mentioned above.

In the case of the adhesive compositions according to the invention compounds contained as polymerization catalysts

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fertilize is open-chain, three- or four-armed and thus branched-chain orthoester podands, the three or four arms containing donor atoms with the general formulas

rh 2 2 rhrh. I rhrh

OJ _n OR ^ R ^ -OLOJ _m O ~ XOLOJ _n O

φ ₂

OLO JpO R ²

Her

O L OJqO-FT

in which X is a central four-bond atom, R water

substance or a short-chain alkyl group, R a short-chain Alkyl group with generally not more than four carbon atoms and m, η, ρ and q integers mean. The central tetravalent atom is preferred a carbon or silicon atom. Preferred orthoester podands are accordingly orthoformic acid, Orthoacetic acid, orthocarbonic acid, orthomethylsiliconic acid and orthosilicic acid esters and mixtures thereof. Good results are also achieved with orthoester podands

1 2
achieved, in which R and R are independently a methyl, ethyl, n-propyl, isopropyl, η-butyl or isobutyl group.

The chain length of the polyethylene glycol chains of the orthoester podands can vary within a wide range. Polyethylene glycol chains have proven to be favorable

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sen, for which the numbers m, η, ρ and q take on values, which are between 2 and 50 and preferably between 3 and 20. For values of m, η, ρ and q over 50, lets In general, there is no additional significant acceleration in the bonding of wood with oo-cyanoacrylate find out more.

By using the adhesive compositions according to the invention becomes the usual inhibition of the polymerization of Q ^ cyanoacrylates on wood and others Substrates with porous / acidic surfaces. Due to the beneficial effect of the polymerization catalysts described is an admixture to the Qi cyanoacrylates only in amounts of 0.01 to 10 wt.% and preferably 0.01 to 5% by weight (based on the total weight of the adhesive composition) required, whereby, for example, wood bonds of excellent mechanical strength are obtained. at all adhesions carried out occurred after one Storage at room temperature for 24 hours when testing the tensile shear strength in the tensile test Wood on.

It was also surprisingly found that the addition of the three- or four-armed Orthoesterpodanden to ^ -Cyanoacrylaten not just a further shortening of the setting

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time when bonding materials with inhibiting, acidic surfaces, especially of wood, but also a crucial one Caused improvement in the storage stability of adhesive compositions produced in this way.

It is known that Q ^ cyanoacrylates, depending on the production conditions and the stabilization during storage, tend to more or less premature polymerization and / or agglomerate formation. This behavior manifests itself particularly evident in implementation of accelerated aging in the storage test at 70 ⁰ C. Substituting now Q ^ cyanoacrylate batches that tend to agglomerate in the vapor space, polymerization catalysts of the invention based on the Orthoesterpodanden to, can be in the storage test at 70 ° C (5 days) observe the complete absence of agglomerate formation.

Another decisive advantage of the invention Orthoesterpodanden can be seen in their good synthetic production, which takes place in high yield from low molecular weight, cheap starting materials and through the elimination of unwanted by-products is particularly economical. The synthesis of the low molecular weight Polyethylene glycol monoethylene ester of orthoformic acid

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and its homologues are described in DE-OS 20 62 034 and US Pat. No. 3,903,006. However, these documents relate to the use of the esters mentioned as
Component of hydraulic fluids.

In contrast, the polyethylene glycol monoether esters of orthocarbonic acid, of orthocarbonic acid, of Alkylsiliconic acid and orthosilicic acid are new compounds represent.

The synthesis of the orthocarboxylic acid esters was made by acid Catalyzed conversion of the lower alkyl esters (methyl, ethyl esters, etc.) of the ortho acids in question with azeotropic distillation of the low levels formed Alcohols carried out using a suitable tractor (e.g. benzene, toluene). For the representation of the alkyl silicone acid esters and the orthosilicic acid ester became the corresponding chlorosilanes with polyethylene glycol monoethers implemented.

They are advantageously used as polymerization catalysts serving three- and four-armed orthoester podands in the form of a solution in an organic solution ' agent in the adhesive compositions according to the invention brought in. For example, anhydrous aromatic hydrocarbons such as benzene, Toluene and xylenes. But it can also chlorinated aliphatic hydrocarbons such as methylene chloride, ChIo-

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roform or carbon tetrachloride are used, without affecting the storage stability of the adhesive compositions being affected.

example 1

15.9 g of trimethyl orthoformate, 100 g of anhydrous tetraethylene glycol monomethyl ether, 0.1 g of 4-methylbenzenesulfonic acid and 300 ml of anhydrous toluene were refluxed with the aid of a packed column with the top of the column attached. The fraction boiling at 64 ° C an azeotrope consisting of methanol and toluene was distilled off until when switching on total reflux for no drop in the boiling point of toluene (110 ⁰ C) was more noticeable. After the reaction had ended, the reaction mixture was cooled, and the toluene solution obtained was extracted by shaking with aqueous NaHCO ^ solution, with Na_S0. dried and the solvent was distilled off in vacuo. 99.3 g (97.6 % of theory) of crude tris (tetraethylene glycol monomethyl ether) orthoformate were thereby obtained
(colorless liquid) obtained.

To remove unreacted tetraethylene glycol monomethyl ether the crude product was distilled in a high vacuum. Initially, at a push of 8 χ 10 mbar and an evaporator temperature of 130 C 11.8 g of a colorless liquid are distilled off. Of the

- 5 ο

The residue was at 5 10 mbar / 250-260 C again distilled, 84.9 g (89.3%) of pure trisftetraethylene glycol monomethyl ether) orthoformate was received

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An adhesive composition of 9.8 g of ethyl-2- cyanoacrylate (thickened with 8.7% by weight polymethyl methacrylate and stabilized with 10 ppm polyphosphoric acid, 50 ppm SOp and 500 ppm hydroquinone) and 0.2 g of a 50% solution of tris (tetraethylene glycol monomethyl ether) orthoformate made in anhydrous toluene. A mixture without the addition of the polymer was used for comparison ions accelerator rs produced.

With the compositions described were overlapping Bonding of test specimens measuring 80 χ 25 χ 6 mm made of different woods was carried out. The setting time was determined as the value at which there was already a clear connection of the parts to be joined in the tensile test was detectable by hand. The results obtained are summarized in the following table:

Setting time of the adhesive composition at 23 C in seconds on test specimens stored in an indoor climate

without polymerisation accelerator with polymerisation wood type accelerator

Limba 50-80 6-8

Beech 180 - 210 15 - 20

Spruce approx. 240 25 - 30

Oak approx. 360 20 - 25

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When determining the tensile shear strength in a tensile test After 24 hours of storage at room temperature, all test specimens showed material breakage in the wood.

The accelerated aging of the adhesive composition described was used to determine the storage stability carried out at 70 C for 5 days. It was found that after this time, that of the usual Storage at room temperature of approx. 1 year, both for those containing the polymerization accelerator Adhesive composition as well as the comparative sample not containing it neither a viscosity increase an increase in the setting time was recorded.

Example 2

37.3 g of anhydrous polyethylene glycol 350 monomethyl ether, 2.9 g of tetramethyl orthocarbonate, 150 ml of anhydrous toluene and 50 mg of 4-methylbenzenesulfonic acid were refluxed with the aid of a packed column with an attached column head. The reaction mixture was distilled off as in Example 1. This gave 34.2 g (89.2 %) of crude tetrakis (polyethylene glycol 350 monomethyl ether) orthocarbonate.

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Mbar by high vacuum distillation at a pressure of 2 χ 10 and an evaporator temperature of 140 ⁰ C, 9.0 g of a distillate obtained which-350 monomethyl polyethylene glycol consisted essentially of. The remaining distillation residue was 24.1 g of pure tetrakis (polyethylene glycol 350 monomethyl ether ) othocarbonate.

The setting times and storage stability were determined as in Example 1 on an ethyl 2-cyanoacrylate adhesive composition, which is 2% of a 50% solution of tetrakis (polyethylene glycol 350 monomethyl ether) orthocarbonate contained in anhydrous toluene. This resulted in the following values:

Setting time of the adhesive composition
at 23 ° C in seconds on test specimens stored at room climate

without polymerisation accelerator with polymerisation wood type accelerator

Limba 50-80 1-2

Beech 180 - 210 3-5

Spruce approx. 240 8-10

Oak approx. 360 5 - 8

Storage stability after 5 days at 70 C: unchanged
Tensile shear strength on test specimens as in Example 1 after 24 hours: material breakage

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Example 3

28 g of anhydrous polyethylene glycol 350 monomethyl ether were initially charged and 3.4 g of freshly distilled tetrachlorosilane were added dropwise at 5 ° C. within b minutes with stirring. The reaction mixture was stirred at 5 ° C. for a further 10 minutes. After stirring for 3 hours at room temperature, the mixture was heated to 80 ° C. for a further 4 hours. The crude product obtained (28.6 g, 100 %) was freed from low-boiling components in a high vacuum.

- 5th

At a pressure of 2 10 mbar and an evaporator temperature of 170 C, 3.2 g of a colorless liquid distilled off. The residue consisted of 24.1 g (84.6 %) of tetrakis (polyethylene glycol 350 monomethyl ether) orthosilicate.

An ethyl 2-cyanoacrylate adhesive composition which contained 1 % of a 50% solution of tetrakis (polyethylene glycol 350 monomethyl ether) orthosilicate in anhydrous toluene gave the following values for the setting time on wood:

Setting time of the adhesive composition
at 23 ° C in seconds on test specimens stored at room climate

Type of wood without polymerization
accelerator with polymerization
accelerator Limba 50-80 2-3 beech 180-210 3-5 Spruce approx. 240 5-6 Oak approx. 360
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Storage stability after 5 days at 70 ° C: unchanged
Tensile shear strength on test specimens as in Example 1 after 24 hours: material breakage

B e i_s_p i_e] _ 4

An E thy] -2 -cyarioacry] at ~ Chra rye, soft boa lage
tended to form agglomerates in the gas space in polyethylene bottles, was thickened with 8.7% by weight of polymethyl methacrylate. A part of this mixture was additionally admixed with 2% by weight of a 50% by weight solution of tetrakis (polyethylene glycol 350 monomethyl ether) orthocarbonate
given. Both adhesive compositions were stored at 70 ° C. for 5 days. The adhesive composition which did not contain a polymerization accelerator according to the invention showed strong agglomerate formation on the vessel wall in the gas space, whereas the adhesive composition containing the polymerization accelerator according to the invention was completely free of agglomerates.

ka: kö

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BATH ORIGINAL

Claims (8)

"cl £ XKÜl.L; & STOL-EE ₁ RG professional PAIENlANWAHt Bt'lüRC THl [UIiOP [AN PATENT BESELEHSTRASSE 4 D JOOO HAMBURG 52 DR J D FRHR by UEXKULL DR ULRICH GRAF STOLBERG DIPL ING JÜRGEN SKCHANTKC DIPL ING ARNULF HUBER DR ALLARD by KAMEKE DR KARL HEINZ SCHULMEYER Teroson GmbH (16824) Hans-Bunte-Strasse 4 Heidelberg July 1, 1980 Cyanoacrylate adhesive composition Claims Adhesive composition based on o £ cyanoacrylate and customary additives, characterized in that they are a polymerization catalyst or several compounds from the group of 3- or 4-armed and thus branched-chain orthoester podands of the following general formulas rh 2 ÖJO —R ² _Λ I rhrh ₂ 2 rhrh rhrh _R '__x — ο L ο J _n OR ^ R ^ —o L o J _m o — χ -— o L o JpO- OJ _p O - R- 0 LOJ _q 0 -— R ² contains, in which X is a tetravalent atom, R Hydrogen or a short chain alkyl group, R 130063/0490 a short chain alkyl group and m, η, ρ and q mean whole numbers. 2. Adhesive composition according to claim 1, characterized characterized in that the central tetravalent atom is a carbon or silicon atom. 3. Adhesive composition according to claim 1 to 2, characterized in that the orthoester podands have polyethylene glycol chains for the numbers m, η, ρ and q assume values between 2 and 50, preferably between 3 and 20. 4. Adhesive composition according to claim 1 to 3, da- 1 2 characterized in that the radicals R and R independently of one another a methyl, an ethyl, an n-propyl, an isopropyl, an n-butyl or represent an isobutyl group. 5. Adhesive composition according to claims 1 to 4, characterized in that the Orthoesterpodanden orthoformic acid, orthoacetic acid, orthocarbonic acid, Are orthomethylsilicone or orthosilicic acid esters. 130063/0490 6. Adhesive composition according to claim 1 to 5, characterized in that it contains 0.01 to 10 wt.% and preferably 0.01 to 5% by weight of the orthoester podands. 7. Adhesive composition according to claim 1 to 6, characterized in that the ^^ - cyanoacry 1 at the general formula CH ₂ = CCT III has, in which R is a straight-chain or branched-chain Alkyl group which may be substituted with a halogen atom or an alkoxy group, a straight or branched chain alkenyl group, a straight or branched chain Alkynyl group, a cycloalkyl group, an aralkyl group or represents an aryl group. 8. Adhesive composition according to claim 7, characterized characterized in that R is a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a pentyl group, a hexyl group, an allyl group, a methallyl group, a crotyl group, a propargyl group, a cyclohexyl group, a 130063/0490 302512? Benzyl group, a phenyl group, a cresyl group, a 2-chloroethyl group, a 3-chloropropyl group, a 2-chlorobutyl group, a trifluoroethyl group, a 2-methoxyethyl group, a 3-methoxybutyl group or a 2-ethoxyethyl group means. 130063/0490