DE1570468A1 - Adhesive and process for its production - Google Patents

Description

PATENT LAWYERS DR. F. ZUMSTEIN - DR. E. ASSMANN DR. R. KOENIQSBERQER - DIPU-PHYS. R. HOLZBAUER TELEPHONE: 22 34 76 and 221911 TELEGRAMS: ZUMPAT SMONOHEN 2,

BRAUHAUSSTRASSE 4 / III POSTAL ACCOUNT: MONOHS O11SO

BANK ACCOUNT: BANK H. AUFHAUSER

(2/3/1)
DCP. 3924

. Expl.

DTJNIOP RUBBER COMPANY LIMITED, 1 Albany Street, London N.W.1, England

Adhesive and process for its production.

The invention relates to pressure-sensitive adhesives and a Process for their manufacture.

The pressure-sensitive adhesive of the invention contains a fully crosslinked reaction product of one or more polyols with at least three hydroxyl groups per molecule or without one or more diols and / or one or more monocles and an organic polyisocyanate, the reaction product being has an average chain length of 130 to 285 chain atoms.

The process of the present invention for producing these pressure-sensitive Adhesive consists in that one or more

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Polyols with at least three hydroxyl groups per molecule with or without one or more diols and / or one or more Monools are reacted with the stoichiometric amount of an organic polyisocyanate, the hydroxyl-containing Compounds are present in sufficient quantity, depending on their molecular weights, to form a fully crosslinked To form reaction product with the polyisocyanate, which has an average chain length between 130 and 285 chain atoms having.

The stoichiometric amount of an organic polyisocyanate is understood to mean that amount of this polyisocyanate which is required to react with all hydroxyl groups of the polyols, diols and monools in order to have a completely crosslinked To form reaction product.

The term “chain length ¹¹ in the sense used here is the length of a chain, expressed in chain atoms, and measured from a branch point to the adjacent branch of a side chain of the first-mentioned chain or measured from the branch point of the first-mentioned chain to the end of the first-mentioned Chain, if there is no branch at one end, understood.

The term "chain atom ¹¹ " only refers to the atoms in the main chain and does not include the side chain atoms.

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The reagents are preferably applied in a flowable state to a substrate such as paper or tissue or a thin one Plastic wrap where they react to form a pressure-sensitive adhesive.

The term "pressure sensitive adhesive" in the sense used here refers to a mass that remains tacky over a wide! Temperature range, namely at least -2O ⁰ C to 7O ⁰ C, and on most surfaces liable _for if in the temperature of the environment in the absence of Low pressure is applied to heat, moisture or other means.

The polyols used according to the invention can be hexols, e.g. sorbitol, pentols e.g. arabitol, tetrols e.g. Pentaerythritol or triplets, such as z «, B. Glycerin. Also copolymers these polyols with propylene oxide and / or ethylene oxide can contain the unmodified polyols Find use. Examples of diols that can be used are Poly (ethylene glycol) and poly (propylene glycol). Examples for usable monools are ifetliyloxitol and n-butanol «

Various combinations of hydroxyl-containing compounds, ie monools, diols, triols, etc., can be used in the invention, for example a single type of tetrol or triol, mixtures of different tetrols and / or triols with different molecular weights, mixtures of one or more types of diols, and mixtures yov ^ ner

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or several types of tetrol and / or triol and one or several types of monool. However, it is regardless of which one Combination of hydroxyl-containing compounds is used, it is essential that such amounts are used that when reacting with an organic polyisocyanate, the mean chain length of the reaction product between 130 and 285 Chain atoms. For example, if a single triplet of the glycerol-propylene oxide copolymer type is used, it should have a molecular weight between about 4000 and 8000 if it is with a low ^ molecular polyisocyanate is implemented. The range can be lower when reacted with a high molecular weight polyisocyanate will.

The mean chain length of the reaction product, expressed as the number of atoms in the chain that correspond to a given Polyol and a particular polyisocyanate is formed is determined by the following procedure. For example become a copolymer of glycerine and propylene oxide with a molecular weight of 5000 with the stoichiometric Amount of 4,4'-diisocyanatodiphenylmethane implemented. The ■ mean total atomic weight of each arm of TriolB is taken as J) OOO, i.e. 1,666 accepted. Each arm of the triplet will assumed that it consists of propylene oxide units (-CH (CH,) - CHp-O-) and each unit has a total atomic weight of 58, which is believed to have only three atoms, viz corresponds to the chain atoms -C-C-O-. The number of chain atoms in each arm of a triol unit of the reaction product is therefore 1,666 χ 3, i.e. 86. The 4,4'-diisocyanate

58 "
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Diphenylmethane units in the reaction product have the lOrmel -CO-IfH-C ₆ H ₄ -CH ₂ -C ₆ H ₄ -IiH-GO ₅ for which the number of chain atoms is assumed to be 11 (with three _{for each -C 6} H _{4 group} Chain atoms are assumed) «Therefore the chain length of the reaction product is on average 86 + 11 + 86, ie 183 chain atoms. Conversely, this method can be used to determine which polyol / polyisoeyanate mixtures will produce a reaction product which has an average chain length between 130 and 285 chain atoms.

If one or more triplets or one or more diols with a organic polyisocyanate are implemented, one finds

more consistent

that pressure-sensitive adhesives with iaesiatai ± g] e3nBXL properties are formed when the triols have low molecular weights, for example 100 to 500 and the diols have high molecular weights, for example 1000 to 3000.

If a mixture that has at least one triol and at least contains a diol, proportions which theoretically provide a poorly pressure-sensitive adhesive, i.e. one that is too hard, and in practice results in a reaction product which has good properties as shows pressure-sensitive adhesive. This is due to the occurrence of a change in the chain lengths of the reaction product. A high percentage of Ketten ™ length with an average of 130 to 285 chain atoms Mixtures are created whose proportions do not-.expect would let, that they have a good pressure sensitive adhesive mask

"if the reaction product obtained were ideal. Under "Ideal" is understood to mean the length of all chains of the reaction product is equal to.

The organic polyisocyanate used in the invention can be aliphatic or aromatic, e.g. 4 »4'-diisocyanatodipheny! methane, Toluene diisocyanate, hexamethylene diisocyanate, Triphenylmethane triisocyanate, 2,4,4'-triisocyanatodiphenyl ether and polymethylene polyphenyl isocyanate.

Usually an accelerator such as dibutyltin dilaurate or tin 2-octoate is added to the reaction mixture prior to curing.

Optionally, an antioxidant can also be incorporated into the reaction mixture prior to hardening or gelling. This stabilizes the adhesive against loss of tack when exposed to air.

The pressure-sensitive Elebmassen according to the invention have the advantage that they do not have to be dissolved or dispersed in a solvent or dispersing agent in order to be applied to a substrate and that the degree of stickiness and non-transferability of the composition is in a wide temperature range, namely from -20 ° C to +120 ⁰ C does not change significantly.

The following examples are intended to illustrate the invention.

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~ 7 -

1570488

example 1

In this example, portions τοη 10 g of different 'triols with different molecular weights are individually mixed with 4,4'-Mis0cyanatodiphenylmethan in the presence of 0.1 g of bibutyltin silaurate as an accelerator and it is shown that only those IrIoIe _{9 have} the molecular weights in

calculated area for the formation of τοη reaction products

having n with average chain lengths 130-285 Kettenaiomen V are suitable. The amount of diisocyanate used in each case was the calculated stoichiometric amount for reaction with any hydroxyl groups present. Further details can be found in Table 1, where the following abbreviations have been used for the sake of simplicity

MS = Molecular Weight of the 5PrIoIs.

DOM = amount of 4.4 ^t -DiisocyaBatoöipkea ^ l methane in g.

RPGL = Mean Sesame Toa as each chain length of the

Reaction product.
GLA = number of atoms in each chain length of the reaction product,

! Table I.

MS SPM RPGL CLA

21 114 149 185 218 325 909834/1500

A. 500 12.75 450 B. 3000 1.28 2250 G 4000 0.953 2916 D. 5000 0.75 3582 E. 6000 0.625 4250 9000 0.425 6250

The triols used in this example were all commercially available and were all copolymers of glycerine and propylene oxide, with the exception of the triol with a molecular weight of 9,000, which is a terpolymer of glycerine and propylene oxide with an ethylene oxide unit at the end of each arm of the Represented triplets.

The RPCIf and CIA values were calculated by the method described above, using the total atomic weight of the propylene oxide units in each arm of the triol by molecular weight

minus /
9000 as 3000 / «Tim total atomic weight of a triolethylene oxide unit (-CHg-CHg-OH), ie 3000 - 45 = 2955, and the number of chain atoms as a result of the two ethylene oxide units of the reaction product (-CH ₂ -CH ₂ -O-) with 6, ie two units per chain was assumed.

Mixtures A through F were then cured. Mixture A cured in a few minutes at room temperature. The mixture B cured slowly at room temperature, but at 70 ^° C. in one hour. The mixtures C to E cured at 70 ⁰ C in 1 1/2 hours. The mixture P cured at 70 ^° C. in two hours.

The properties of the crosslinked reaction products obtained are shown in Table II:

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- y _

Table II

A = hard, brittle - firm.

B = Not sticky, rubber-like solid. C = a little softer and stickier than B. D = soft, non-transferable, somewhat sticky, semi-solid

(Adhesive value = 217 g).
E = soft, non-transferable, sticky, semi-solid (adhesive value

= 45 g).
P - Very soft, transferable, very sticky, semi-solid.

From this it follows that of the mixtures A to P only mixtures C, D and E are suitable for use as pressure sensitive adhesives.

The adhesive values of mixtures D and E were at room temperature measured with a Dunlop tackmeter (British Patent 741 214).

Example 2

This example shows the manufacture and properties a pressure sensitive adhesive made from a mixture of triplets of different molecular weights became .

A mixture of 10 grams of a molecular weight triol 4000, 10 g of a triol of molecular weight 5000, 20 g

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of a triol with a molecular weight of 6000, 2.99 g of 4,4'-diisocyanatodiphenylmethane and 0.3 g of dibutyltin dilaurate were cured ^{at 70 ° C. for about 1 1/2 hours.} The cross-linked reaction product obtained was pretty tough, shows no sign of tJfeertragbarkeit at 100 ⁰ C and had a probe tack value of 516 g.

Example 3

This example shows the production and the properties of a pressure-sensitive adhesive composed of a mixture containing a triol and a diol.

4 Mixtures G through J were made using various triols and diols as shown in Table III in all Parts represent parts by weight.

In Table III, the following abbreviations have been used for the sake of simplicity used:

5000T = copolymer of glycerine and propylene oxide from

Molecular weight 5000.
300T = copolymer of glycerine and propylene oxide with a molecular weight of 300.

1500D = poly (propylene glycol) with a molecular weight of 1500. 2000D = poly (propylene glycol) with a molecular weight of 2000. DDM = 4.4 ^I- diisocyanatodiphenylmethane. DZD = dibutyltin dilaurate.

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α 2. - 5 • Table III . 10 - 1. H 500OT - 0. 2 "' . 10 300T 1 - ■ 1500D 200QD - 2.0 ' BSM 1.0 " DgD 0.1.

Oo 1

Each of Mixtures G- to -S wait 1 1/2 hours at 70 G to form a somewhat soft, tacky reaction product. The adhesives for the reaction products of Mixtures-S to J were 600 g, 580 g, 550 g and 770 g Is found that the blends gave I and J reaction products, but these were less sticky in ko'jasisisenter iiaren properties when Eeiliesfertlgsiag than the mixtures G and H. germ of Beaktionsproäiikte seen was any evidence of tfeertragbarkeit "at 100 ⁰ O ₉ '

Example 4

This example shows the preparation and properties of a pressure sensitive elephant mass made from a mixture of a triol and a monool.

4 Mixtures K through N were made as shown in Table IV in all parts represent parts by weight.

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In Table IV, the following abbreviations have been used for the sake of simplicity used:

6000T, 5000T and 4000T = copolymers of glycerine and

Propylene oxide with molecular weights of 6000, 5000 "and 4000.

MO '"= methyl oxytol.

DM and DZD = as "in Table III.

Table IV

6000T 10 I. 005 - 5000T - 64 10 4000T - 1 - MO 0. 0.028 DDM 0. 0.80 DZD 0. 0.1

10

0.010 0.96 0.1

10 0.020 0.97 0.1

Mixtures K to N were cured at 80 ° C. for 1 hour and the properties of the reaction products obtained are shown in Table V.

Table Y

K = fairly hard, non-transferable, adhesive 380 g. L = fairly soft, poorly transferable, adhesive value 385 g. M = fairly hard, non-transferable, adhesive value 463 g. N = Quite hard, not transferable, adhesive value 480 g.

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The adhesive values given in this description were at room temperature with a Dunlop Tadaneter (British Patent 741 214) measured.

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Claims (1)

P a t t n t a η ε ρ r il c u ι 1 «j Pressure-sensitive adhesive, characterized by a Content of a fully crosslinked reaction product β ι nee or ■ Several poly oils with at least three hydroxyl groups per Molecule with or without one or more diols and / or a or several monools and an organic polyisocyanate seed, which has an average chain length between 150 and 285 ettenatoaen. 2. Kebdc according to claim 1, characterized in that they also contains an antioxidant. 3. Process for the formation of a pressure-sensitive adhesive mask, characterized in that one or more fol> ols with at least three hydrochloric groups per molecule with or without one or more sols and / or one or more Monoole with the stuchiome tr laugh set an «organic Polyisocyanate vergesetat verden, whereby the hydroxyl-containing Yert) indungen in sufficient quantity rorliagen, usi depending on τοη their · »molecular weight a completely reaped most Form reaction product with the polyisocyanate su, welchee • A mean warp days τοη 130 Ma 285 lettenatcsum having. 9Q983A / 1500 4 «A method according to claim 3» de ^ oroh gekennseieimst, Q && one or more triols bit one pole ;, isceyanat integrated in another poly oils _s diol or monocle be · 5. The method according spoke 3 ₉ characterized in that «In friol and« in. Monool bit «ine» polyisocyanate in the absence of any «veinous? Olyol8 or biols become uncured · 6. Procedure according to AnepruciL 3, thereby identifying Monool meth; loxytoi is confused. ? · Method according to address 4 "5 or 6" characterized in that the friol is a llischpol ^ beer of glycerine and prop :, leLox: -d salt "ine" Holekuiargevricht jswiechen 40Oo and 8000 iet. 8. The method according to claim 7 »thereby marked * that molecular weight of the triol is 5,000. 9. The method according to claim 3 »characterized in that a sriol and a mol ait of a Polyieoc; .anat in the absence of any other TtIoIb or diol or monool. 10. The method according to claim 9, characterized in that the triol has a molecular weight of 100 to 500 and the diol BATH ORIGINAL • la has a molecular weight between 1000 and 3000. 11. The method according to claim 9 or 10 »characterized in that the · Trlol is a copolymer of CHycerol« ad propylene oxide let · 12 «Method according to claim 9» 10 or 11, characterized in that da · Slol Poly (prop :, lengly col) 13. Y * rfthr «n nmch · 1χμμ d« r claims 5 to 12, thereby e «k« o & selch8Mt, that the · polyleocymnat «la diisocyanate let · 14 · Yerfthrea aach lneprmch 15 _t thereby g «k« mui «lchiMt _t dafi ale dileocyanate 4» 4 ^t -Dll * ocyanatodlpheiyl »« th «n used vlrd. 15. Yerllahren aach "the acceptance 3 hl · 14" thereby marked, that the reactloneelechunf "la Antloxydation" - »Lttel is incorporated. 16. Proceed as follows: AepreUche 3 bl · 15 »thereby marked that the 1-3ctloa-1, "chuag" in Beechleomiger is incorporated 17. The method according to claim 16, thereby calculated that as accelerator dibutylmin dilaurate is used. 18 · Yerfahren according to one of the claims 3 bl · 17 »thereby 909834 / 1S00 BAD OR ₁ GINAL Keansel paves the way for the beagentles to be brought to the state 9, ut a substrate and allowed to react there with the formation of the pressure-sensitive adhesive. 909834/1500