DE2209529C3 - Use of a prepolymer obtained from polyalcohols and polyisocyanates - Google Patents

Description

for impregnating paper or a similar porous carrier material, with 20 to 80% by weight of the reaction product a) added and the remaining isocyanate groups with the active Hydrogen of the carrier material are implemented.

2. Use according to claim 1, characterized in that for the preparation of the reaction product a) instead of or in addition to the polyalcohol a hydroxylated elastomer is used <r, namely

x) a copolymer of styrene and butadiene with a styrene content of 15 to 20% or

y) a copolymer of acrylonitrile and butadiene with an acrylonitrile content of 10 to 20% or '"

z) polybutadiene,

the elastomer having hydroxide numbers between 20 and 60, the proportion of trans groups 57 to 63%, the proportion of cis (l-4) groups 19 to 21% and the proportion of vinyl (1-2) groups 19 to 21%.

This invention relates to the use of a

Solution

ii) a reaction product of a polyalcohol with a molecular weight of 800 to 3500 or from mixtures of polyalcohols with molecular weights between 400 and 4400 and one

IVlÖlcKÜItll gC W I

Poly alcohol mixture from 800 to 3500 with 1.8 to 2.5 equivalents of isocyanate of an aromatic polyisocyanate with different reactive isocyanate groups, namely toluene diisocyanate and Dipolyisocyanates of ethyl benzene, xylene, ditoluene, methyldiphenylmethane, dimethyldi-phenylmethane and dianisidins;

b) a catalyst in a proportion of 0.1 to 6% of the weight of reaction product a), namely

u) tin (! I) salts of an organic acid having 1 to 22 carbon atoms;

v) dibutyltin dilaurate, dibutyltin diacetate, dioctyltin diacetate, Dibutyltin maleate and / or

w) a tertiary amine, namely trimethyl, triethyl, tripropyl and tributylamine, N-methylmorpholine, N-ethylmorpholine or triethylenediamine in an amount of 10 to 100% of the weight of the tin compounds (u and V);

c) an inert organic solvent with a boiling point around 175 ° C, in particular Toluene,

for impregnating paper or a similar porous carrier material, wherein 20 to 80 wt .-% des Reaction product a) added and the remaining isocyanate groups with the active Hydrogen of the carrier material are implemented.

Comparable prepolymers are known from US Pat. No. 3,437,622. The known prepolymers are applied to an inert carrier, for example on paper, and result after evaporation of the solvent a pressure-sensitive adhesive. Penetration of the prepolymer into the carrier, there is no intention to modify this if necessary and this is not done with this citation described.

The invention is based on the object of such prepolymers for the internal strengthening of paper and other porous carrier materials that still contain active hydrogen to be used.

The inventive solution to this problem is characterized in that paper or the like porous carrier material with active hydrogen with the above solution taking up from 20 to 80 wt .-% reaction product a) is impregnated and the remaining isocyanate groups with the active hydrogen are implemented.

A preferred embodiment of the above use is characterized in that for the production of the Reaction product a) used instead of or in addition to the polyalcohol, a hydroxylated elastomer will, namely

x) a copolymer of styrene and butadiene with a styrene content of 15 to 20% or

y) a copolymer of acrylonitrile and butadiene with an acrylonitrile content of 10 to 20% or

z) polybutadiene;

wherein the elastomer has hydroxide numbers between 20 and 60, the proportion of trans groups 57 to 63%, the proportion of cis (1-4) groups 19 to 21% and the proportion of vinyl (1-2) groups 19 to 21% amounts to.

After the inventive impregnation of paper, a product is obtained which has a vVcSCniiiCii CriiöiitC ι ruCKCriicäugKCii üfiu WCaCnuiCii

has increased wet strength; furthermore is the resistance of the product to dissolution increased in individual layers while still maintaining a satisfactory flexibility. The received Product can be used for numerous purposes, for example as a sealing material, Carrier for abrasive medium !, artificial leather, shoe insoles, insoles for removing adhesives, Carrier for gummed adhesive tapes. Preferably, the product obtained is used as a carrier for pressure-sensitive Adhesive tapes used

Polyalcohols with a molecular weight between 800 are suitable for producing the prepolymer and 3500; furthermore, mixtures of polyalcohols with a molecular weight of approximately 400 to about 4400 are suitable if these mixtures have average molecular weights between 8CO and 3500; the average molecular weight of such mixtures is preferably between 1000 and 3200. A polyalcohol with a molecular weight of 400 is therefore used to produce such a mixture used, it must be mixed with a sufficient amount of the higher molecular weight polyalcohol so that the average molecular weight of the mixture is brought to a value that is not is below 800 and not above 3500 Commercially available products can be used, such as polyether trialcohols with molecular weights of 1500, 2500 or 3000, another A suitable polyalcohol is the polydialcohol known under the trade name "Carbowachs" a molecular weight of 600; an adduct of propylene oxide to 1,2,6-hexane dialcohol can also be used Success can be used. Also polyhydroxy ethers, such as substituted polyalkyl ether glycols or Polyhydroxy polyalkyl ethers are well suited.

Instead of or in addition to the polyalcohols mentioned, it is also possible to use liquid, hydroxylated elastomers be used; especially suitable s.'ch:

1. A copolymer of styrene and butadiene with a styrene content of 15 to 20%, preferably 20%, with a hydroxide number of 42, with a proportion of trans groups of 60%, a proportion of cis (l-4) groups of 20% and a content of vinyl (1-2) moieties of 20%, having a viscosity of 295 poise at 30 ⁰ C, a density of 0.91 g / cm ³ and an iodine number of 335;

2. a copolymer of acrylonitrile and butadiene with an acrylonitrile content of 10 to 20%, preferably 15%, with a hydroxide number of 39, with a proportion of trans groups of 60%, a proportion of cis (-4) groups of 20 % and a proportion of vinyl (1-2) groupings p of 20%, with a viscosity of 500 poise at 30 ^° C., a density of 0.92 g / cm ³ and an iodine number of 345;

3. a polybutadiene with a hydroxide number of 45, with a proportion of trans groups of 60%, a proportion of cis (l-4) groups of 20% and a proportion of vinyl (l-2) groups of 20% , with a viscosity of 200 poise at 30 ⁰ C, a density of 0.9 g / cm ¹ and an iodine / .ahl of 345th

The hydroxide numbers can vary from 20 to 60;

UlC AMiiciic an ι ι aim-, \ ^. Ιλ- uiiu ν iiiji-vji uppivi ungvn can vary from 57 to 63% or from 19 to 21% or from 19 to 21%; the viscosities can range from + 5% to -5% and the iodine numbers also vary from + 5% to -5%. These hydroxylated elastomers can be used instead of the abovementioned polyalcohols or in a mixture with any proportions of these polyalcohols be used.

The polyisocyanate used must have at least two isocyanate groups of different reactivity. It is intended that the more reactive isocyanate groups in the course of the preparation of the Prepolymers largely react, while the less reactive isocyanate groups during the production and the subsequent storage - "> tion and handling of the prepolymer react only insignificantly at room temperature; the less reactive isocyanate groups should only react after the selected carrier material impregnated with the prepolymer and additional catalyst and at higher temperatures has been heated. In the course of this heating, the less reactive isocyanate groups should react with the active hydrogen of the selected carrier material.

2) Already 2,4-toluene diisocyanate has a sufficient Difference for the reactivity of the isocyanate groups. Also through the presence of other neighboring groups such as chlorine, the desired different reactivity of the isocyanate groups can

Jd be made. Suitable polyisocyanates are, for example 2,4-toluene diisocyanate and the polyisocyanates of ethylbenzene, xylene, ditoluene, methyldiphenylmethane, Dimethyldiphenylmethane and dianisidines. For example, commercially available toluene diisocyanate

r. be used, which consists essentially of 80 wt .-% 2,4-isomer and 20% by weight of 2,6-isomer.

The polyalcohols are mixed and reacted with the polyisocyanates in proportions such that to 1 equivalent of hydroxide of the polyalcohol 1.8 to

4Ii 2.5 equivalents of isocyanate fall.

In the context of the invention it was found that the reaction conditions under which the less reactive isocyanate groups react with the active hydrogen of the carrier material, special concerns

4-, interpretation is important; It is desirable that the carrier material impregnated with prepolymers should not be heated for more than 3 to 4 minutes; Jind provided for the heating temperatures at or above 160 ⁰ C, the duration of this heating, 1 min is not

, ο exceed. In order to achieve sufficient in these short periods of time The selection of the catalysts is of particular importance to ensure reaction.

Suitable catalysts are, for example, in US Patents 33 97 158, 33 92 128 and

-, -, 33 98 106 described; this includes tin (ll) octoate, Tin (II) oleate, optionally mixed with a tertiary amine, tin (II) salts of an organic acid with 1 to 22 carbon atoms, optionally also in a mixture with a tertiary amine,

hu tin (IV) compounds such as dibutyltin dilaurate and other organic tetravalent tin compounds and tin (II) neodecanoate. Suitable tertiary Amines are trimethyl-, triethyl-, tripropyl- and tributylamine, also N-methylmorpholine, N-ethyl-

I ₁ -, morpholine, triethylenediamine, triethylamine being preferably used. It is also possible to use primary and secondary amines if the number of iSGCyaPiaigrüppCn SuSrCiCiii, mil uem uäfi'iii ill UaS Kcak-

tion mixture introduced active hydrogen to react.

The common use of fertile amines and tin (lI) catalysts are already known; Additionally it was found that tertiary amines also have a synergistic catalytic effect with tin (IV) catalysts Show effects; it was also found that primary and secondary amines also use these show synergistic catalytic effect with both tin (II) and tin (IV) catalysts. Tin (IV) catalysts are particularly effective in this context

Dibutyltin dilaurate, dibutyltin diacetate,
Dioctyl tin diacetate and dibutyl tin maleate

The catalyst used is a mixture of tin (II) and / or tin (IV) catalysts with primary, secondary or tertiary amines are used, this can result in the final heating of the prepolymer impregnated carrier material can be shortened to a few seconds, compared to a period of time minutes, using the most active tin catalysts without adding amines at the same time. The proportion of amine to tin catalysts can be 10 to 100% of the weight of the tin (II) or tin (IV) catalysts used; is preferably the amine content 10% by weight. The proportion of tin catalysts is 1 to 6% of the weight of the Reaction product of polyalcohol and polyisocyanate.

The prepolymer obtained from polyalcohol and polyisocyanate is soluble in organic solvents such as benzene, toluene, xylene or mixtures thereof. The solubility is retained even if up to 30% by weight of a volatile, liquid aliphatic, alicyclic hydrocarbon such as, in particular, heptane is added to the organic solvent. Other suitable solvents are the acetates of monomethyl, monoethyl or monobutyl ethers of ethylene glycol, ethyl acetate, ethers and ketones such as methyl ethyl ketone. For all solvents it is required that these are largely inert and neither react with the isocyanate groups nor with the polyalcohols. Because of its low price and suitable volatility, toluene is usually used in a mixture of up to 30% by weight of heptane. Unk-r standard conditions to the boiling point of the solvent under 175 ° C, preferably below 120 ⁰ C, are. The proportion of the prepolymer in the impregnation solution can range from 20 to 80% by weight and is usually around 40 to 50% by weight.

According to the invention, paper or similar porous carrier materials are used with the selected solution, containing active hydrogen, impregnated. The presence of active hydrogen can, for example according to the method of Zerewitinoff (reports 40.2023 [1907], 41.2236 [1908]) or according to the Contribution to J. Amer. Chem. Soc. 49, 3181 (1927) determined will. Materials with active hydrogen are, for example, substances that contain hydroxide, amino, Contain carboxyl and certain other groups; for example cellulose, cellulose ester, Cellulose ethers, polyvinyl alcohol, partially hydrolyzed polyvinyl esters, alkyd resins, gelatine, casein, leather, gelled vegetable oils and similar materials. Preferably, the selected solution is used for Used for impregnating paper.

The following examples serve to illustrate the invention without restricting it.

example 1

104 kg polyether trial alcohol with a molecular weight of 1500, 263 kg of polyether trial alcohol with a molecular weight of 2500 and 38.5 kg of commercially available Toluene diisocyanate (with 80 wt .-% 2,4-isomer and 20 wt .-% 2,6-isomer) were in a solvent mixture dissolved from 51.2 kg of heptane and 120 kg of toluene. The resulting solution is in a

ίο jacketed mixer for about 1 hour at temperatures heated between 82 and 93 ° C, then cooled and stored for 16 hours at 27 ° C; Analyzes of this product show that the major part of the hydroxide groups from the trial alcohols with the {socyanatgruppen responded. This solution was 1.36 kg of tin (II) octoate were added. An endless paper tape which had been drawn off a roll was passed through this solution and then removed excess solution by means of nip rollers; such an amount of solution was taken up that the finished, solvent-free paper increased in weight of about 50%. After passing through the nip rollers, this was with solution saturated paper passed through a hot air oven,

2 ^r > where the temperature was kept at the beginning at 52 ° C and at the end at 177 ° C. The total residence time in the furnace was 1.5 to 3 minutes, and after most of the solvent had evaporated, such an amount of steam could be allowed towards the end of the drying treatment

jo be introduced that no condensation occurs the paper was done to saturate the remaining isocyanate groups; with sufficient heating during this drying treatment, however, the supply of steam can generally be omitted.

A largely non-stick product is obtained, which has good flexibility and noticeably improved wet- and dry strength, as well as increased resistance to dissolution into individual layers and good Has solvent and temperature resistance.

Example 2

The impregnation was essentially analogous to Example 1 Paper made. The deviation existed

π mainly in the fact that in addition to the trialcohols 35.3 kg of low acid number resin was added; this resin content made about 25% by weight of the prepolymer from; the acid number of this resin was slightly below 4. In the event that the resin is active

-, o contains hydrogen, the added amount had to be Polyisocyanate can be increased accordingly. Suitable resins can, for example, by polymerization unsaturated hydrocarbons obtained from petroleum; furthermore are terpene-indene resins or

v, coumarone-indene resins are suitable. Furthermore, a neutral or slightly acidic solid filler such as kieselguhr, aluminum silicate or lamp black can be added to the prepolymer in proportions of up to about 25% by weight.

Example 3

Trial alcohol with a molecular weight of 3000 was mixed with commercially available toluene diisocyanate in a molar ratio 1 mol of trial alcohol to 3 M-> l! > iisocyanate at tr-, 93 ° C brought to reaction.

The reaction medium used was 50% by weight of toluene. The solution obtained was kept at 27 ° C for 24 hours, without any noticeable change in viscosity

emerged. 1% by weight was used as the catalyst. Tin (! L) -Ock> at. based on the total weight of the Prepolymers, added. By the kutuiysatorhaitige The solution was paper hi; 'irf-: ri-h led and with this Solution saturated. After drying, analogous to example ι ..,. 'Rde eir, bi ^^: -._ :: χ · ι material obtained, Jas fr. i .on was stickiness; compared to the original the paper used has increased the weight of the product by 45%; the resistance to a The resolution into individual layers was from 66 to 440 g / cm, its dry strength from 1.62 to 4.96 kg / cm and its wet strength increased from 0 to 3.24 kg / cm.

Example 4

The impregnation was essentially analogous to Example 3 Paper made. The main difference was that instead of the one used there Trial alcohol is an adduct of propylene oxide and 1,2,6-hexane trial alcohol with a molecular weight of 1500 was used. The product obtained was free of stickiness and showed a weight gain of 49%; its resistance to dissolution in individual layers had from 66 to 490 g / cm, its dry strength from 1.62 to 5.22 kg / cm and his Wet strength increased from 0 to 3.42 kg / cm.

Comparative example

In this comparative example, the procedure of Example 4 was essentially repeated; the The difference was that instead of the adduct used there, glycerine was used as a polyalcohol was used. The paper obtained after impregnation and drying was found to be very stiff.

It must be noted here that the molecular weight of glycerol is considerably below that according to the invention intended limit of at least 800 for the molecular weight of a suitable polyalcohol. On the other hand, when a trial alcohol with a molecular weight of 4400 was used, it was found the paper obtained after impregnation and drying is very rubbery and soft. It was found, that with such a use of a polyalcohol with too high a molecular weight too few crosslinks occurred, so that an unsatisfactory product was obtained as a result.

Example 5

One mole of the reaction product that is produced in the gradual addition of propylene oxide to Dipropylengiycoi with a molecular weight of 2000 erhaiicii will,. »- iii'c mil 2 Mo! commercial toluene diis ;; cvaiiat in 50 i> ew .-% Toitio! .m: reaction brought.

After adding before. Catalyst was passed through the resulting paper solution. After j: i ^r i, rächender drying, the increase in weight was 40%: the resistance GOG ^ n resolution in individual layers had from 66 to 440 g / cm, the ~ I curl strength before, I.62 on 4.PfS kg / cm and the \ l _; >, Rfp <; tj-i. _c jt increased from 0 to 3.24 kg / cm.

Example 6

51 kg of dialcohol with a molecular weight of 1/2000, 313 kg of trial alcohol with a molecular weight of 4400, 195 kg of trial alcohol with a molecular weight of 2500 and 90 kg of commercial toluene diisocyanate were reacted in toluene and a solution containing 40% by weight of prepolymers was obtained. After addition of 2 » catalyst, paper was passed through this solution and then dried. The product obtained showed a weight increase of 60% and its resistance to dissolution into individual layers was from 66 to 490 g / cm, its dry strength from 1.62 to 5.94 kg / cm and its wet strength from 0 to 3 , 42 kg / cm increased.

Example 7

20 kg trial alcohol with a molecular weight of

in 4400, 2.3 kg dialcohol with a molecular weight of 600, 4.5 kg of resin from polymerized unsaturated hydrocarbons and 4 kg of commercial toluene diisocyanate were reacted in toluene and a solution containing 60% by weight of prepolymers was obtained. To

r> addition of catalyst was made through this paper Solution passed through and dried. The product obtained showed an increase in weight of 55%, his Resistance to dissolution into individual layers was from 66 to 380 g / cm, its dry

; i: strength from 1.62 to 4.50 kg / cm and its Wet strength increased from 0 to 3.24 kg / cm.

In all cases the determination of the wet and Dry strength with the known "Scott tester", in each case with a 2.5 cm strip of the obtained

j-, paper. To determine the resistance to dissolution into individual layers, a 2.5 cm wide strip of a peel-off strip firmly glued on, then started to tear off and then measured the force required to terminate the tear-off

-, ii was required.

Claims (1)

Patent claims: 1. Use a solution a) a reaction product of a polyalcohol with a molecular weight of 800 to 3500 or from mixtures of polyalcohols with molecular weights between 400 and 4400 and an average molecular weight of the polyalcohol mixture from 800 to 3500 with 1.8 to 2.5 equivalents of isocyanate of an aromatic polyisocyanate with different reactive isocyanate groups, namely toluene diisocyanate and dipolyisocyanates of the i ~> Ethyl-benzene, XyIoIs, Ditoluols, Methyldiphenylmethans, Dimethyldiphenylmethane and dianisidine; b) a catalyst in a proportion of 0.1 to 6% by weight of reaction product a), ai namely u) tin (II) salts of an organic acid having 1 to 22 carbon atoms; v) dibutyltin dilaurate, dibutyltin diacetate, dioctyltin diacetate, dibutyltin maleate> ^r > and / or w) a tertiary amine, namely trimethyl, Triethyl, tripropyl and tributylamine, N-methylmorpholine, N-ethylmorpholine or triethylenediamine in an amount of 10 to 100% of the weight of the tin compounds (u and v); c) an inert organic solvent with a boiling point around 175 ° C, in particular Toluene, Γι