SE444320B - PROCEDURE FOR THE PREPARATION OF COMPOSITION FILES WITH ISOCYANATE ADHESIVE - Google Patents

Description

A further object of the present invention was to find a process for composite films which in a technologically less expensive way leads to clear, adhesive composite films.

This object is solved according to the invention in that one of the two films to be glued together on one or more polyethers bearing at least two terminal isocyanate groups, whose molecular weights are between 2000 and -5000 and which are made of polyether diols derived from glycols with 2-4 carbon atoms and on the second film apply one or more long chain compounds bearing at least two reactive amino groups prepared from polyether diols or oligomeric glycols having a molecular weight between 200 and 4500, the molar ratio of isocyanate groups to amino groups being between 1: 1 and 5; 1 and both components together are present in an amount of 0.5-5.0 g / m2, and compress the two foil surfaces formed for a short time.

Suitable at least bifunctional isocyanates useful for the process according to the invention can be prepared by reacting anhydrous polyether diols with at least bifunctional isocyanates in a manner known per se. The polyether diols are derived from glycols containing V2-4 carbon atoms. Consequently, polyethylene and / or polypropylene glycol and / or polytetramethylene glycol (produced by ring-opening polymerization of tetrahydrofuran) are in question. In particular, relatively low molecular weight diisocyanates are involved in the reaction with the polyether diols, such as hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, dicyclohexylmethane diisocyanate, isophorone diisocyanate, toluylene diisocyanate (isomer mixture) and several others. For practical, especially toxicological reasons, diphenylmethane diisocyanate is preferred. For the formation of the isocyanate adduct, a reaction ratio of 1.8: 1 to 2.211 (moles of diisocyanate = moles of diol) is preferably suitable. A smaller turnover ratio is in principle also possible provided that an excessively high-viscosity adduct is not obtained in the use of which an unobjectionable mechanical lamination is no longer obtained.

A possible turnover ratio greater than 2.2: 1 would in principle also be tolerable if, for toxicological reasons, there are no concerns about the thereby high content of free diisocyanate.

Care must be taken that the isocyanate compounds obtained during processing do not exceed a viscosity of about 10,000 cP. Optionally, this reactant can be applied even at elevated temperatures to about 80 ° C. In general, however, temperatures of 50-65 ° C are preferred.

Laminating glues which are carried out only with at least two isocyanate groups having the adducts having the adducts as isocyanate component in combination with the amine compounds mentioned below as amine component give sufficient adhesive strengths. However, it has been found that these can be significantly increased if 0.5 to 20, preferably 1.0 to 10% by weight of a compound having at least 3 isocyanate groups is added to the isocyanate adduct, the weight amounts relating to the isocyanate adduct. With the isocyanate component thus modified, a higher initial tack is achieved in particular, but also an improved final adhesive strength. Suitable additive compounds with at least 3 isocyanate groups are reaction products of multifunctional alcohols and diisocyanates (conversion ratio: one mole of diisocyanate per hydroxyl group), for example the reaction product of trimethylolpropane and toluylene diisocyanate, and reaction products of one mole of water and 3 moles of starting diisocyanate. methylene diisocyanate, furthermore also other aromatic triisocyanates, such as 4,4 ', 4 "-triisocyanatotriphenylmethane and also polyisocyanates such as polymethylene polyphenyl isocyanate.

In order for the resulting isocyanate mixtures to be easily applied to the film webs during mechanical lamination, they must be heated in the application vessel in order to reduce the processing viscosity.

A temperature increase to a maximum of BOOC must not be exceeded. In general, a temperature of GOOC is completely sufficient. Up to this temperature, upon lamination with the isocyanate component described in Example 1, it was determined by measurements at the laminating machine that no isocyanate concentration exceeding the permissible MAK value of 0.02 ppm occurred in the workplace atmosphere. The second reactant used for the process of the invention is a least bifunctional amine. At least two amino groups must be present that can be both primary and secondary; Such compounds are known resp. produced in a known manner. A backbone of the amino compound is the polyether diols or even oligomeric glycols. According to a suitable embodiment, the procedure is such that acrylonitrile is deposited on the polyether diols. The resulting adducts are then hydrogenated in a known manner, whereby primary amino groups are formed by the V nitrile groups. polyether glycols derived from polyethylene glycol; polypropylene glycol and polytetramethylene glycol having a molecular weight of between about 200 and 4500, in particular 300 and 2000.

Furthermore, it is possible to start from relatively low molecular weight diamines with a chain length of 2 ~ 18 carbon atoms which in part can also Varäf fi ßåt fi äfmïísyfêäümßr and react these diamines with compounds containing at least 2 amine-reactive functional groups (chain extension); Such amines are, for example, HZNf-CH2 -CH2-CH2-O ~ - (CH2) 2 -_- ¿-o - cH2-cHA2 ~ cH2-NH2 HZN-CH2f-CflzfifiCH2 -~2 (-CH2f- CH2 ¥ -Oå_š ~ CH2 -CH2-fCH2 * -NH2 or even 0% p I '' (m3. - 'I / I, »_ \\ CH 3 H2N" -' p 'CÅ; or 112N - (cf12 The functional groups of the chain extender can then be, for example, epoxide or isocyanate groups or also dL, ε -unsaturated esters or halogen atoms. The OH groups, secondary amino groups or urea groups formed in this reaction or introduced ester clusters can in some cases have a favorable effect on the adhesion or strength of the adhesive compound.

In the case of a diepoxide or diglycidyl compound CH2- ~ c1 ~ 1-- n-cn - cH-¿or cnzv flfl vnwcæm-Ö-R-focza -cn-c fi- \ / \ / \ o / »OO carbon atoms, for example methylene, ethylene , propylene, neopentylene, hexamethylene, dodecamethylene, cyclohexylene, dicyclohexyl, methylenedicyclohexyl or even a diethylene or triethylene glycol ether residue, and the diprimary amine corresponds to the general formula H N-R'-NH2 2 'wherein R' represents, for example, an ethylene ~, tetramethylene-, hexamethylene-, diethylene glycol ether, dipropylene glycol ether- or even a triethylene- 2 Vi wherein R is an aliphatic or cycloaliphatic group having up to 25 'propylene ~; 7803857-7 glycol ether residue, compounds containing two terminal primary amino groups of the general formula on 'on HZN-M R' --ru1- ~ cn2- ~ cu --- R --- cix - c112 --- 1: H - n'e-NHZ I-case-chain extension with isocyanates, for example toluylene, hexamethylene and isophorom fi isogenate, compounds containing two terminal amino groups and urea groups of the general formula 'n nm R f --- NH- ~ c are obtained -ä r-IHWRWNH-f C - x11IU-1áfQ-NI12 - wherein R 'has the previously indicated meaning while R represents the remainder of the isocyanate used. The chain extension reaction for suitable amines is further described in German patent application P 25 49 371.4.

In many cases it may be appropriate to add the longer chain compounds bearing amino groups 1-50% by weight, preferably 1-15% by weight of water. Thereby, one can bring about an increase resp. an earlier achievement of the final strength and sealing ability of the composite foil is favorably affected.

In the case of mechanical lamination, a sufficient one is spontaneously formed. high initial tack so that no delamination or "telescoping" of the composite foil occurs during winding. Within 7 days after manufacture, the adhesive strength when stored at room temperature reaches its final value. The adhesive films are then chemically crosslinked and show a condition that is technically sufficient for all requirements regarding composite adhesion and heat resistance, which is a prerequisite for the sealability.

The finished laminates are further characterized by very good optical properties. Thus, for example, transparent laminates show high transparency. Otherwise commonly occurring lamination defects such as "fisheye" or "orange peel structure" cannot be determined for the laminates. With the described two-component laminating adhesive, all laminates can be made of plastic foils, such as polyethylene, poly-polyester, polyvinyl chloride, polystyrene, polyamide foils, etc. Furthermore, the production of composite foils using metal foils is possible, for example aluminum foil, or even different cellophane types resp. paper. The process according to the invention is further illustrated by the following examples. The compounds referred to in the examples as "aminopropylated" polypropylene glycols are prepared by the addition of acrylonitrile to the glycol and subsequent catalytic hydrogenation. Example 1) Component extract 2000 g of isocyanate adduct of polypropylene glycol having a molecular weight of 2000 and diphenylmethane-4,4 ' in a molar ratio of 1: 2 and 100 g of reaction product of 3 moles of hexamethylene diisocyanate and 1 mole of water. Content of free isocyanate groups: 4.0% resp. 1.0 mE / g viscosity via 2300; 25,000 op viscosity via 50 ° c = 8,000 op viscosity via 60 ° c = i '2,500 oP (always Brookfield viscosity) Component B: 300 g aminopropylated polypropylene glycol (average molecular weight 400) 500 g aminopropylated polypropylene glycol (average molecular weight 2000) Amine content: 2 1.6 mU / g I 'I 1.68 g / mg of the component A heated to 60 ° C was mechanically applied to the polyester foil (foil thickness 12 μm) and 0.35 g / m2 of component B at room temperature on low-temperature polyethylene foil pretreated by corona discharge. density (foil thickness 50 pm). The molar ratio of isocyanate to amine component, calculated on isocyanate to amine groups, was 1.9: 1. The coated sides of the foil were compressed over rollers. The adhesive film showed a high spontaneous initial tack (30 seconds after gluing, a peel adhesive strength of 30 p / 15 mm was measured at a peel rate of 100 mm / minute).

After 8 hours of lamination time, the components were allowed to be processed well further when forming an unchanged high initial tack. Due to the increase in viscosity, the application rate of the isocyanate component increased to 1.92 g / m2 while the application rate of the amine component remained constant at 0.35 g / m2. This gave a molar application ratio of 2.2: 1.

After 7 days of storage at room temperature, a peel strength of 350 p / 15 mm had been set. This value was determined? Aø3as7-7 both at a laminate piece which was produced at the beginning, and also one which was made at the end of 8 hours of laminationL “1.

Example 2.

Component A:. 0 I. '.

Isocyanate adduct of polypropylene glycol (average molecular weight 2000) and diphenylmethane-4,4'-diisocyanate in a molar ratio of 1: 2.

Content of free isocyanate groups: 3.4% resp. 0.81 mE / g viscosity at z3 ° c = '' 20,000 cp viscosity at 60 ° c = 2.ooo cp ComEonent_§: 300 g aminopropylated polypropylene glycol (average molecular weight 400) 500 g aminopropylated polypropylene glycol (average molecular weight 2000) Aminhait; 2.5 mm / g * '' 2.1 g / m2 of the component A heated to 60 ° C was applied to the aluminum foil (foil thickness 12 mm) and 0.4 g / m2 of component B was applied to low density polyethylene foil pretreated by corona discharge. (foil thickness 50 μm) .V The molar ratio of the components was 1.7: 1 (isocyanate: amine group).

When joining the coated foil sides, a sufficiently high initial tack was achieved (peel strength: 6 p / 15 mm at 100 mm / min peel rate 30 seconds after production). _ _ '_ _ w After 7 days of storage, the final strength (250 p / 15 mm) was reached. '' I Exemgel 3.

Component A: 2000 g isocyanate adduct of polypropylene glycol (average molecular weight 3000) and diphenylmethane-4,4'-diisocyanate in a molar ratio of 1: 2 and 100 g of reaction product of 3 moles of hexamethylene diisocyanate and 1 moles of water. Content of free isocyanate groups: 3, 3% resp. 0.79 mE / g viscosity at 23 ° c = 29,000 CP viscosity at 60 ° C = 6,000 cp Component B: 0 Aminopropylated polypropylene glycol (average molecular weight 400) 7803857 ~ 7 Amine content: 5 mE / g 2.56 g / m2 of it to 60oC heated component A was applied to the polyester foil (foil thickness 9 μm) and 0.2 g / m 2 of component B to aluminum foil (foil thickness 12 μm). The molar ratio between the two components then, based on isocyanate and amine group, was 2 = 1. , '_ I Initial tack (30 seconds after gluing together): 15 p / 15 mm. I p A siuthålifasthet- (after 7 eyes) = 300 p / lá mmj_ Example 4.

Component A: 2000 g isocyanate adduct of polypropylene glycol (average molecular weight 2000) and diphenyl 4,4'-diisocyanate in a molar ratio of 1: 2 and 100 g of reaction product of 3 moles of hexamethylene diisocyanate and 1 mole of water V 2 Vi Content free isocyanate group 4.2% resp. 1.0 mE / g viscosity at 23 ° c = 0 25,000 CP viscosity at 60 ° C = V 2,500 CP Component B: 300 g aminopropylated polypropylene glycol (average molecular weight 400) 500 g aminopropylated polypropylene glycol (average molecular weight-2000) and 2 '0 20 g of water ~ V Amine content: 2.44 mE / g 2.17 g / m2 of the component A heated to 60 ° C was applied to polyester foil (foil thickness 12 μm) and 0.41 g / m2 of component B at room temperature of by corona discharge.preformed low density polyethylene film (film thickness 40 μm). The molar ratio between the components was 2.2: 1 (isocyanate: amine) § Initial tack (30 eec customers after gluing together): 10 p / 15 mm. 0 I 'Final strength (after 3 days): 380 p / 15 mmw

Claims (4)

7sosss747 «PATENTI _ <_ RAV á I 1. A process for producing composite films using isocyanate adhesives, 'characterized' by applying to one of the two films to be glued together one or more polyethers bearing at least two terminal isocyanate groups, the molecular weights of which are between 2000 and 5000 and which are made from polyether diols derived from glycols having 2-4 carbon atoms and on the other film apply one or more long-chain compounds bearing at least two reaction-prone amino groups made from polyether diols or oligomeric glycols having a molecular weight of between 200 and 4500, the molar ratio of isocyanate groups to amino groups being between 1z1 and 5: 1 and both components together being present in an amount of 0.5-5.0 g / m 2, compressing the two film surfaces formed for a short time. 2. A process according to claim 1, characterized in that the polyether bearing isocyanate groups is added. 0.5-20, preferably 1-10% by weight of a compound bearing at least 3 isocyanate groups, the amount being calculated after the polyether bearing isocyanate groups. 3. A process according to claim 1 or 2, characterized in that the reaction products of polyethers with acrylonitrile which are then hydrogenated are used as compounds bearing at least two reaction-prone amino groups. 4. A process according to any one of claims 1-3, characterized in that the compound bearing amino groups is added to 1-50, preferably 110% by weight of water, the amount being calculated on the compound as here amino groups.