DK142350B - PROCEDURE FOR THE MANUFACTURE OF LAMINATE WRAPS - Google Patents

Description

(11) PRESENTATION OF LETTERS 1 2 3 5 O

DENMARK m m a- I “® C 09 J 5/04” (21) Arvøgnning no. 46 ^ 0/76 (22) Filed on 14th. October 1976 (24) Running Day 1 4 · Oct · T 97 6

(44) The note presented and Q

to submit to the Ice Scribe published on the 20th. October I 9o0

DIRECTORATE OF

PATENT AND TRADEMARK (3 °) Priority requested from it

Nov 4 1975 * 2549571, DE

(71) HENKEL COMMANDING COMPANY ON SHARE, Henkel troussse 67, D-4000 Uuesseldorf 1, DE.

(72) Inventor: Hans Bauriedel, Am Falder 101, 4000 Duesseldorf 13, DE: Rainer Hasenkamp, Schinkelstrasse 21, 4006 Erkrath, DE.

(74) Plenipotentiary in the proceedings:

The company Chas. Hude.

(54) Process for producing laminate sheets.

The invention relates to a process for the preparation of laminate films using solvent-free adhesives based on multifunctional isocyanates and multifunctional coreactants.

Laminate sheets are generally made by means of solvent-containing caching adhesives applied by rollers to a film web. Thereby, the bonding with the second web occurs under short-term pressure after the evaporation of the solvent. As adhesives in this method known as dry caching, almost exclusively solvent-containing polyurethane systems are used in the form of moisture-curing isocyanate end-distilled prse polymers or two-component polyol / polyisocyanate mixtures. The recent limitations of solvent releases to the atmosphere necessitate absorption or post-combustion of the solvent / air mixtures as costly process steps.

German Patent Laid-Open No. 1,694,079 discloses a process for producing multi-layered materials, wherein a film is made from polyolefins and cellophane or polytexephthaiate. The characteristic of this method consists in the use of polyhydroxy polyethylene reaction products, which turnover products contain free NCO groups. Such products are known in principle for the production of isocyanate adhesives, but such adhesives are applied either without further addition or, preferably, together with crosslinking components such as polyhydric hydroxyl compounds directly on the adhesive films. The cross-linking component is added to the isocyanate-containing component immediately prior to the preparation of the laminate, and thus is an adhesive system which immediately begins to react and can therefore only be used within a limited processing time.

Furthermore, from German publication specification No. 1,909,755, a method for bonding a wide variety of materials is known. In the disclosure, the process is referred to as a rapid mechanical process for obtaining adhesion at room temperature or slightly elevated temperature using solvent-free reaction adhesives based on polyhydroxy compounds and polyisocyanate compounds. However, the adhesives used in the process are highly accelerated adhesive systems which, after continuous mixing, are applied to the surface to be bonded. Thus, a non-durable reactive system is formed if two adhesive component components, together with the respective accelerator, are dosed between the material parts to be bonded.

In the method of the present invention, in contrast, a two-component adhesive is used if two different components are separately applied to the sheets to be joined together.

Such a mode of operation could previously only be at issue in the case of rigid materials which, after the application of the adhesive system to two reactive components, could still be displaced against one another so that a mixing would occur.

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The present invention is directed to the use of an adhesive system for laminate foil manufacturing which is free of solvents and therefore can be treated more fire or explosion proof and further enables a more economical process.

Another object of the present invention is to provide a process for the manufacture of laminate foils which results in clear, cohesive solid laminate foils in a technologically only slightly demanding manner.

This is achieved by a method of the type mentioned in the preamble, characterized in that one of the two adhesive films is applied to a polyether which carries at least two terminated isocyanate groups, and to the other film to apply longer chain compounds. at least two terminal primary amino groups, the molecular weights of which compounds are between 300 and 2000, wherein the molar ratio of isocyanate groups to amino groups is between 1: 1 and 2.0: 1, and the two components together have a layer thickness of 1.0 to 6 µm. , and that the two coated foil layers are briefly compressed.

Hereby, surprisingly good adhesions are obtained, since the mixing of the two components of the adhesive can practically be effected only by diffusion.

Suitable, at least useful bifunctional isocyanates useful in the process of the invention can be prepared in a manner known per se by reaction of anhydrous polyhydric diols with at least bifunctional isocyanates. Preferred polyether diols are derived from glycols containing from 2 to 4 carbon atoms. Accordingly, polyethylene and / or polytetramethylene ether glycol (produced by ring-opening polymerization of tetrahydrofuran) is included. In the first instance, relatively low molecular isocyanates are considered for reaction with the polyether diols such as hexamethylene diisocyanate, isophorone diisocyanate, toluylene diisocyanate (isomer mixture), etc.

It should be borne in mind here that the resulting isocyanate compounds during processing must not have a viscosity of more than 8000 to 9000 cP. Optionally, this reaction component can also be applied at slightly elevated temperatures of up to approx. 50-60 ° C. Generally, however, temperatures of 20-30 ° C are preferred.

The second reaction component used in the process of the invention is a at least bifunctional amine. It can be built from the same basic skeleton, namely polyether diols. In a convenient embodiment of the process according to the invention, it is stated that as compounds with at least two primary amino groups, polyethylene-containing acrylonitrile reaction products which have subsequently been hydrogenated are used. Hereby primary amine groups are formed from the nitrile groups.

For the preparation of the two reaction components in the solvent-free caching adhesive, polyether glycols are preferred, and a preferred embodiment of the invention is characterized in that polyethylene glycol or polypropylene glycol, polyethylene glycol or polypropylene glycol-based polyether ethers are used. ca. 200 and 1500.

Furthermore, it is possible to assume relatively low molecular diamines having a chain length of 2 to 18 carbon atoms, which may be partially replaced by oxygen atoms, and to react these diamines with compounds containing at least two amine-responsive functional groups (chain extension). Such amines are, for example, h 2 n - ch 2 - ch 2 - ch 2 - o - (ch 2) 2 - 4 - 0 - ch 2 - ch 2 - ch 2 - n 2 H 2 N - CH 2 - CH 2 - CH 2 - 0 (-CH 2 -CH 2 -O) 1_3-CH 2 - ' CH2 - CH2 - NH2 or ^ 3 V. -Nry- ch2 - ch3 ch3 or H2N - (CH2) 6_g - NHg.

The functional groups may be, for example, epoxide. or iso = cyanate groups or α, β-unsaturated ester groups or halogen atoms.

The OH groups formed by this reaction, secondary amino groups or urea groupings or introduced ester groupings may, as the case may be, have a favorable effect on the adhesion or the strength of the adhesive compound.

In the case of a deep oxide or a diglycidyl compound B in which R represents an aliphatic or cycloaliphatic group of up to approx. 25 carbon atoms such as methylene, ethylene, propylene, neopentyl, hexylene, dodecylene, cyclohexylene, dicyclohexyl, methylenedicyclohexyl or diethylene or a triethylene glycol ether group, and the diprimary amine corresponds to the general formula H2N - R '- NH2 wherein R -, butylene, hexylene, diethylene glycol = ether, dipropylglycol ether or triethylene glycol ether group, compounds containing two terminal primary amino groups of the general formula are obtained.

OH OH

I I

H2N - R * - NH - CH2 - CH - R - CH - CH2 - NH - R '- NH2 · In the case of chain extension with isocyanates, such as, for example, toluylene diisocyanate, hexamethylene and isophorone diisocyanate, compounds containing two terminated amino groups and urea groups with the general formula H «N - RT -NH-C-NH-R-NH-C-NH-R * - NH« 2 II II 20 wherein R * is as defined above while R is the group of the isocyanate used .

By using (meth) acrylic acid esters (eg tri or tetra = ethylene glycol di (meth) acrylic ester) for chain extension, compounds of the general formula ^ COROC ^ NH '- R' - NH - CH '- CH CH - CH In which RT is again of the same meaning as above and R is the dialcohol group in the (meth) acrylic ester, i.e. in the e.g. In the cases mentioned, the tri or tetraethylene glycol ether group. Of course, one can also rely on other di (meth) acrylic acid esters of glycols, e.g. ethylene glycol, propylene glycol, butylene glycol, decanediol, etc.

Finally, it is also possible to make a chain link with α, ω-dihalides which proceed according to the same principle in known manner.

In this case, compounds of the general formula H2N - Rf - MH-R-NH-R4 - NH2 are formed, wherein R here represents a group of up to 12 carbon atoms which may optionally also contain an oxygen atom such as, for example, the tetraethylene glycol ether group or the tetrapropylene glycol ether group , and R * has the same meaning as above.

The ratio of diprimary amines to the chain extender must be chosen such that 2 moles of amine are formed approx. 1 mole of difunctional epoxide, isocyanate, (meth) acrylic ester or dihalide. In the reaction, substantially the desired compounds containing at least two terminal primary amino groups are formed, which compounds have a molecular weight of from about Suitably, the viscosity of the amine component is somewhat lower than the viscosity of the isocyanate component. It has proved practical to work towards a viscosity of approx. 50 to 1200 cP at 20 to 30 ° C.

Thus, the two reaction components are applied via rollers to the foils that isocyanate groups and amino groups are present in the molar ratio of ca. 1: 1 and 2: 1.0. In addition, the amount is adjusted to form an adhesive film with a total thickness of 1.0 to 6.0 μηι.

The film surfaces coated with the two components are compressed between a pair of rollers which may also be partially heated. On the way to the laminate settlement, a sufficient primary adhesion is formed, which may be increased by means of heat supply, e.g. using hot air.

7 142350

The process of the invention enables caching at relatively high speeds. Use of drying channels is not necessary. After the compression of the sheets, no displacement between the webs or a partial delamination is observed. After winding the sheets onto rolls, the sheets must be stored for an additional 3 to 7 days at room temperature depending on the layer thickness of the adhesive film and the reaction tendency of the reaction participants. Within this time, the final strength appears. The cohesive strength of the laminate obtained is in most cases so high that delamination is no longer possible without material overgrowth.

By means of the process according to the invention, laminate foils comprising the components polyethylene (pretreated), polypropylene (pretreated), cellulose hydrate in lacquered and unpainted form, polyethylene terephthalate, polycaprolactam, polyvinyl chloride, aluminum and other metals can be prepared.

Example 1

Component A: Isocyanate adduct of polypropylene glycol (average molecular weight 410) and trimethylhexamethylene diisocyanate = 1: 2 molar ratio (molecular weight 830).

Content of free isocyanate groups: 10.1%

Viscosity at 25 ° C: 3500 cP (Brookfield).

Component B: Aminopropylated polypropylene glycol (average molecular weight 410) prepared by the addition of acrylonitrile to the glycol and subsequent catalytic hydrogenation (theoretical molecular weight 524).

Amintal: 170-180

Viscosity: 60 cP (Brookfield). 1 2.5 g of component A is applied to 1 m by corona discharge pretreated low density polyethylene film (film thickness 50 μη), and 1.56 g of component B is applied to 1 m polyester film (film thickness 12 μη), which corresponds to application film thicknesses of approx. - 8 142350 team approx. 2.5 µm and 1.56 µπι, and the coated sides of the sheets are joined by rollers. The adhesive film showed spontaneous initial stickiness, and 30 seconds after adhesion, a delamination adhesive strength of 3 to 5 p / 15 mm (of tensile velocity 100 mm / min) was measured. After four days of storage, splitting of the foil laminate is no longer possible without tearing the foils.

Example 2

Component A: Isocyanate adduct of polypropylene glycol (average molecular weight 630) and trimethylhexamethylene diisocyanate in the molar ratio of 1: 2 (molecular weight 1050).

Content of free isocyanate groups: 8.0%

Viscosity at 25 ° C: 5000 cP (Brookfield) at 50 ° C: 1000 cP

Component B: Aminopropylated polypropylene glycol (average molecular weight 630) prepared by the addition of acrylonitrile to the glycol and subsequent catalytic hydrogenation (theoretical molecular weight 744).

Amintal: 142

Viscosity: 130 cP (Brookfield).

o 2 1.0 g of component A is applied to 1 m of pretreated polyethylene film (film thickness 50 µm) and 0.74 g of component B is applied to 1 m of cell glass foil (film weight 31.5 g / in), the molar ratio A: B is 1.02: 1, which corresponds to application film thicknesses of approx. 1 and approx. 0.74 μη and the coated sides joined together by means of rollers. The foil laminate is immediately heated for 10 minutes to 50 ° C. The delamination strength then measured is 5-6 p / 15 mm (peel rate 100 mm / min). After four days of storage, splitting the foil laminate is no longer possible without destroying the foils.

Example 3

Component A: Isocyanate adduct of polytetramethylene ether glycol (average molecular weight 980) and toluylene diisocyanate

Claims (3)

9: 142350 in the molar ratio of 1: 2 (molecular weight 1328). Content of free isocyanate groups: 6.33 Viscosity at 25 ° C: 7000cP (Brookfield). Component B: Amine of Example 1. 2. 1.38 g of component A is applied to 1 m of pretreated polyethylene = foil (film thickness 50 µm) and 0.6 g of component B is applied to 1 m of polyamide foil (film thickness 60 µm), with the molar ratio A: B being approx. 1.1: 1, which corresponds to an application film thickness of 1.36 and 0.6 µm, and the coated sides of the film are joined together by means of rollers. The glued sheets are briefly heated to 50 ° C. The then measured delamination strength is 8-10 p / 15 mm (peel speed 100 mm / min). After four days of storage, splitting the foil laminate is no longer possible without destroying the foils. Claims. A process for preparing laminate films using solvent-free adhesives based on multifunctional isocyanates and multifunctional coreactants, characterized in that one polyester having at least two terminated isocyanate groups is applied to the polyether with at least two terminated foil residues and applied to the other foil. compounds containing at least two terminal primary amino groups, the molecular weight of the compounds being between 300 and 2000, wherein the molar ratio of isocyanate groups to amino groups is between 1: 1 and 2.0: 1, and the two components together produce a layer thickness of 1.1 to 6 µm and that the two coated foil surfaces are briefly compressed. Process according to claim 1, characterized in that, as compounds having at least two primary amino groups, reaction products of polyethers with acrylonitrile which have been hydrogenated are used. Process according to claim 1 or 2, characterized in that polyethylene glycol, polypropylene glycol = polyethers containing isocyanate groups or amino groups are used.