DE2257501A1 - POLYURETHANE-BASED ADHESIVE - Google Patents

Description

IJH. INC ..

I) H. K. ν. 1'HOIl MAN .V I) K. INI !. J) ^ IiKIlItKXS IJlI ¹ Ii. IN";. H. {! OUT /.

Γ AT YY N TAN WΛ I. T K

8 MÜNt-LIK.V »O SCIIWKI (IKIfSTHASSE S!

TELKFON (UMI) (Mi UU Rl TKLRX H 24 U70

τκι.ι: οιιλμμκι pbotkf ¹ tpatk-vt m ('sou ev

1-42 246

Description of the patent application

BORDSN, INC.
50 West Broad Street Colurnbus, Ohio 43216, USA

concerning:
"Polyurethane-based adhesive"

For sticking plastic films on cellulosic and A wide variety of adhesive systems are known from metallic substrates. Although they generally result in good, adhesions resistant to moisture and tubs however, all have one or more of the following disadvantages:

(1) The durability of the bonds is too short;

(2) slow cure and low "green strength";

(3) limited adhesion to a wide variety of Runs-G fabric films.

The invention is therefore based on the object of providing an adhesive with excellent stability, long durability and

409822/0980

to provide good green strength in the tub, the hardens quickly and can be used for as many plastics as possible. In particular, the invention has the The object is to provide an adhesive that, when used with polyvinyl chloride films that are from 0 to 25 wt .- / » Contain plasticizers that have the above properties.

This object is achieved by the adhesive according to the invention, which is curable with isocyanate and, expressed in parts by weight, has the following components: About 2 to 16 parts of a linear polyurethane polymer with a hydroxyl content of at least 0.1 % \

about 4 to 20 parts of an acid modified copolymer of vinyl chloride and vinyl acetate;

about 1 to 5 parts of polyepoxide;

about 0.5 to 4 parts of hydroxyl-containing low molecular weight polyester resin;

about 50 to 90 parts of solvent.

The invention further includes an adhesive, except

(A) still has the above components:

(B) 1 to 10 parts of an isocyanate curing agent.

The invention also relates to the use of the above adhesives for laminates on cellulose or Metal pads.

The polyurethane polymer present in the adhesives of the invention can be any linear polyurethane olyner with one or more free hydroxyl groups (Hydroxylgehalu

- 3 -409822/098 0,

at least 0.1%). Preferably it has at least a moderately high rate of crystallization. The polyurethane polymer adduct gives the adhesives according to the invention important properties. First and foremost is the polyurethane polymer is responsible for the excellent green strength of the adhesive in the heat, which is particularly important applies to the polyurethane polymers with high crystallization rate. The absence of the rest Hydroxyl group in the urethane polymers allows chain extension and crosslinking with the isocyanate as Hardening agent, so that when hardening "a product is obtained which is resistant to both heat and water and also has high adhesiveness. As examples of such polyurethane polymers, Rucothane (P-250-2) and (P-252) manufactured by Hooker Chemical Company which are primarily linear .elastomeric polyurethanes, which are produced by the conversion of an adipate-diol polyester are formed with an aromatic or aliphatic diisocyanate (Desmocoll 400, 405, ΚΔ-8029, 420, manufacturer Farbenfabriken Bayer AG, Q-thane 13 910, 13 920, 13 930, 12 907, manufacturer K.J. Quinn and Co., Inc., and Estane 5711, 5712, 5713, made by B.F. Goodrich Chemical Company).

Optionally, the adhesives can be a mixture of polyurethane polymers with different hydroxyl contents and different crystallization rates included. In this way you can get the green strength and control the flexibility of the cured product.

The low molecular weight polyester resins used in the adhesives also bring free hydroxyl groups into it, which when hardened with the isocyanate residue

40982 2/0980

cross-link and in this way "stretch" the adhesive, so that you get by with lower costs, without valuable Sacrifice properties. The preferred polyester resins have low molecular weights ranging from about 600 to 3,000. Polyester resins with a much higher molecular weight are not compatible with the urethane polymers and can therefore not in the production of the adhesives according to the invention be used. Preference is given to low molecular weight polyester resins which have relatively high hydroxyl numbers (40 to 350) as these resins provide more hydroxyl groups for crosslinking. As examples of such polyester resins from low molecular weight may be mentioned: Krumbhaar 1979 »Manufacturer Lawter Chemicals, Inc .; Pomrez 50, manufacturer Vitco Chemical Co .; Multron R-12, R-16, R-22, R-68, R-74, Manufacturer Mobay Chemical Co .; Wilmar PE-180, PE-508, PE-719 » Manufacturer & y Wilson-Ilartin, Inc.

Among the acid-modified vinyl chloride-vinyl acetate copolymers, preference is given to those which have been modified with an α-β-unsaturated, low molecular weight aliphatic dicarboxylic acid or its anhydride. Particularly preferred is a copolymer which has about 65 to 88 % vinyl chloride and about 0.7 to 2.5 vol of acid or acid anhydride and about 12 to 18 vol vinyl acetate. The aliphatic, olefinically unsaturated acid can include: itaconic acid, maleic acid, acrylic acid, methacrylic acid, protonic acid and fumaric acid. The acid-modified vinyl chloride-vinyl acetate copolymer ensures adhesion to both the vinyl film and the cellulose substrate. It apparently also makes a significant contribution to water resistance and green strength when exposed to heat. It is believed that the carboxyl groups react with the isocyanate radical on curing, thereby lengthening the chain and causing crosslinking, so that both the

409822/098 0.

Adhesive strength as well as the heat and moisture resistance substantially increased «.

Examples of acid-modified vinyl chloride-vinyl acetate resins include: Vinylite VMOA, ViIGH, VMCC, manufacturer Union Carbide Company.

The epoxy resin component contributes to improving the flow properties of the adhesives according to the invention and the wetting of the base. In addition, the epoxy resin acts as a heat stabilizer for the vinyl chloride copolymer and vinyl acetate.

As a wide range of epoxy resins are available commercially When preparing the adhesives according to the invention, one can choose those which are suitable for the desired ones Properties come into question. If, for example, the adhesive should have particularly good wetting properties at lower laminating temperatures use an unmodified liquid epoxy resin such as Araldite 6004, 6005, 6010, manufacturer Ciba Products Company or Epon 812, 826, 828, 830, 834, Manufacturer Shell Chemical Company. Should the adhesive have good wetting properties at higher laminating temperatures and a higher green strength in heat, an unmodified solid epoxy resin such as Araldite 7097, 7071, 6099, 6084 or Epon 836, 1001, 1007, 1010, 1031. These types can be used in a wide variety of ratios used to get a medium effect.

The lower molecular weight epoxy resins have the following general structural formula:

409822/0980

- O CH ₁ OH CH, 0

- ■ - · - CU, CH,

The isocyanate residue is likely to react with the secondary hydroxyl group of the epoxy molecule, lengthening the chain, resulting in greater bond strength. Examples of suitable epoxy resins are the condensation products of bisphenol-A and epichlorohydrin, as well as the condensation products of formaldehyde with phenol or resorcinol, provided they have low molecular weights, such as the dimers and trimers. Examples are bisphenol-A, ie. 2-3 -Bis- (p-hydroxyphenyl) propene; Tetraphenoxyethane; Glycerine and polyethylene or other polyalkylene polysulfide resins such as the "Thiokol" series. Examples of such epoxy resins are: Araldite 6004 ₁ 6005, 6010, 7097, 7071, 6099 and 6084 and Epon 812, 826, 828, 830, 834, 836, 1001, 1007, 1010 and 1031 (see above).

The choice of starting material for the inventive Adhesive was chosen based on the compatibility of the components, the ability of the individual component to contribute to the adhesion and the presence of certain groups in each of the components associated with the isocyanate residue able to react to a complex network, so that structures arise that are opposite to V / poor and. water have high resistance, high green strength in the warmth and are characterized by rapid hardening.

As already mentioned, this is how the hydroxyl groups of the

A09822 / 0980

Urethane polymer, the hydroxyl groups of polyether resin, the hydroxyl groups of the epoxy resin and the carboxyl groups of the vinyl chloride-acid copolymer all with the isocyanate residues, whereby additional urethane bonds are created.

In the production of the adhesives according to the invention, the polyurethane polymer, the vinyl chloride-vinyl acetate copolymer, is mixed Epoxy resin in a suitable solvent or solvent mixture until all Components are completely dissolved. The type of solvent is not characteristic of the invention, it just needs to (1.) be able to perfectly complete the above components to dissolve, (2 *) must not react with the constituents and must (3 ·) result in a mixture that has good processing properties on the roller and has good flow or leveling properties and dries uniformly. Suitable as a solvent methyl ethyl ketone, toluene, acetone, methyl isobutyl ketone, Xylene, cyclohexanone, chlorothene NU, ethylene chloride, Perchlorethylene, trichlorethylene. Preferably the The proportion of pesticides in the agent is between about 10 and about 50 percent by weight.

The isocyanate curing agent is added to the curable mixture added shortly before use as an adhesive.

The adhesives according to the invention can be used for bonding plastics, such as acrylic acid films, Polyethylene films, acrylonitrile butadiene styrene films, Polyvinyl chloride films (with low and high plasticizer content) on cellulosic or cellulosic substrates, such as paper, wood, chipboard, plywood, resin board etc. and on metallic substrates such as aluminum, lead, tin, nickel or steel (which may be surface-treated could be).

409822/0980

The adhesive is applied either to only one or to both surfaces, which are glued together, as is usual in practice. For example, the adhesive can only be applied to the hard surface in two layers, each time being carefully dried. The thus coated substrate is then allowed under an infrared lamp through, so that the Oberflächentemperatrur is 104-116 ° C and then immediately bring the Piim using a hot roll (116-149 ⁰ C) to the hot hard surface, wherein one high as possible Applying pressure. According to another procedure, the adhesive can be applied to both surfaces as follows: Both surfaces are coated once with the adhesive and carefully dried. The coated hard substrate is then passed under an infrared lamp, which increases the surface temperature to 82 to 93 ^° C., and the film, which is also coated with adhesive, is then rolled onto the heated hard substrate under the highest possible pressure and a temperature of about 93 ° C. This two-step process uses less heat for the hard substrate and the roller.

In both cases, the plastic-coated boards and the like can be stored or processed immediately. The according to the invention Due to their good green strength, adhesives hold the plastic film in place when heated and prevent it from lifting or sliding over the edges. The smocks arrive in about two hours high bond strength after use and are within Fully cured for 24 to 36 hours, so that both the adhesive strength and the resistance to heat and moisture are of a quality that has hardly been achieved so far.

The agents according to the invention can optionally contain further ones

409822/098 0,

Contain additives, for example the wetting agents known to the person skilled in the art, such as lecithin "N", manufacturer Central Soya Co. and if necessary the usual »pigments and fillers.

The examples, in which the parts mean parts by weight, serve to explain the invention in more detail.

Example 1

An adhesive was made by mixing the following components at room temperature:

Component parts

Polyurethane polymer having a high crystallization rate and a hydroxyl content of 0.1% (Eucothane P250-2) ¹ 9.20

maleic acid modified vinyl chloride-vinyl acetate copolymer (81% vinyl chloride, 2.0% maleic acid, and 17% vinyl acetate) (Vinylite VIiCA) 10.23

Epoxy resin (Araldite 7O97) ² 2.55

low molecular weight polyester resin

(Krumbhaar 1979P 1.02

Solvent mixture of methyl ethyl

ketone, acetone and toluene 77.00

- 10 -

409822/0980

- -ίο -

Note 1): Rucothane P250-2 is a granular, thermoplastic polyurethane resin with 0.1% hydroxyl groups. The resin is characterized by the following physical properties:

a) Crystallization rate = 60 seconds

(Test: Film of 0.05 mm thickness, heated for 10 minutes in the oven at 71 ⁰ C; liristallisationsgcschwindigkeit observed at 24 ⁰ C.

b) crystal melting temperature = 4-9 C;

c) limit modulus = 28.1 kg / cm;

d) Elongation limit = 15 / °>

e) modulus at 400 '/ * elongation = 42.2 kg / cm ² ;

f) tensile strength = 197 kg / cm ² ;

g) Elongation at break = 615 ^c / ° \

h) Graves tear test, PIT = 400;

i) Melt index 80 ⁰ C (2160 g) = 2.

Note 2): Araldite 7097 is a solid, unmodified epoxy resin. It is characterized by the following physical properties:

a) Weight per epoxy »1650 to 2000;

b) Viscosity (Gardner-Holdt) = X to Z (40 % solids in butyl carbitol);

c) Color (Gardner) = 3 max (40 % solids in butyl carbitol);

d) Specific weight 1.17-

Annotation; 3): Krunbhaar 1979 is a low molecular weight polyester resin with a calculated molecular weight

- 11 -

409822/0930

from 800 to 1,000 and a hydroxyl number from 300 to 330. It is characterized by the following physical properties:

a) acid number = 0.3;

b) Ep. = 96 ° C;

c) * arbe (Gardner 1933) = 2-4;

d) specific weight = 1.33.

To 95 »6 parts of the above approach were made shortly before use 4.4 parts of polymethylene polyphenyl isocyanate were added.

The adhesive was used to make laminates from vinyl chloride film on chipboard as follows:

A solution of the adhesive agent was applied to particle board of 1,3 cm thickness with a layer thickness of 0.075 Επη and the coated plate 30 seconds in the oven at 66 ⁰ G dried. The second, equally thick, spread was then applied and dried at 71 ° C. for 15 seconds. To the experimental conditions of the commercial processing to match the glued plate was then placed in an oven at 171 ° C and held there for 100 seconds, which the temperature of the plate brought to approximately 104-116 ⁰ G; this corresponds to the temperature in the industrial production of vinyl-coated panels. After removal from the furnace a vinyl film (Columbus Coated Fabrics £ -6 Clear Seal) was rolled from 0.15 mm thickness on the hot plate, the roll temperature was 104 ⁰ C and

ο
a pressure of 4.57 kg / cm 1/8 second was applied.

The properties of the vinyl coated particle board were

- 12 -

409822/0980

examined as follows:

Experiment A: The green strength of the coated plate in the heat was tested immediately after the coating. For this purpose, pieces of 2.5 x 12.7 cm were cut out of the coating, the cut extending down to the chipboard. A scale was attached to one end of the film and the film was peeled off at a rate of about 7.6 cm / inch. After about 1.3 cm of detachment, the force required for detachment was read off until the entire piece was detached. As a measure of the green strength in the warm, the average force in kg was taken, which was measured over the entire length of the vinyl film piece; in the present example it was about 94 to 14 kg / m. Commercially available adhesives on the market such as Goodyear Tire and Eubber (Adhesive Division) Pliogrip 91O9A &B; USM Chemical's Bostik 7283A & B, 7286-0 A&B, 7289 White ASiB ₁ would generally give values between about 36 and 63 kg / m 2 under the same test conditions.

Experiment B: The peel force was measured on two-hour-old test pieces as follows: Pieces of Cut 2.5 x 13 cm of the foil down to the chipboard and the specimens in a "Thwing-Albert Universal Testing Machine" at 90 ° and 180 ° for a peel test subjected to a peel rate of 5 cm / min was used. The following average Detachment rates observed:

^ Q ⁰ Detachment speed 180 ° Detachment 3efieschv / i n d i ftk0it 178.6 - 214.3 k _G / m 223.3 - 250 kg / m

67 % - 75 5 "ö plate error 80 % - 90 <for plate error ei 'and and

35 % - 25 ^: } o adhesive error 20 % - 10 ■ »adhesive error

- 13 409822/0980

Commercially available adhesives currently on the market give the following after two hours of aging Values: "

90 ° peeling speed 180 ° peeling speed

89.3 - 125 kg / m 116 - 197.3 kg / m

20 % - 35 % plate defects. 35-55 % plate defects

and and

80 % - 65 % adhesive failure 65 - 4-5 % adhesive failure

Samples of the laminate were stored for 24 hours at low temperature aged and then in a "Thwing-Albert Universal Tasting Machine" as examined above. The following typical results were observed:

90 ° peeling speed 180 ° peeling speed

267.9-303.6 kg / cm ² 278.6-328.6 kg / m

90% - 95% film torn no peeling; Slide at

torn all pieces.

10% - 5% plate defects

Commercially available adhesives currently on the market gave the following comparative values after 24 hours;

90 ° peeling & speed 180 ° peeling speed 196.5-285.6 kg / m 250 - 294.6 kg / m

35 - 65 ^c / o plate defects 65 - 85 % plate defects and. and

65 - 35 % adhesive failure 35 - 15 % adhesive failure

Examination of test pieces which had been aged for 36 and 72 hours at room temperature gave the same values

- 14 - ■

409822/0980

as with the 24 hour old specimens. Example 2

An adhesive is prepared analogous to that from Example 1, but the 9.20 parts of Rucothane P250-2 are replaced by 9.20 parts of Rucothane P252-2 ¹ . The adhesive was used to coat chipboard with vinyl chloride film and tested according to Example 1; In this case, there was a somewhat lower green strength when heated, while the strengths after 2 hours, 24 hours and 36 hours were comparable.

Note 1): ßucothane P252-2 is a granular, thermoplastic polyurethane resin with 0.1 % hydroxyl groups. It is characterized by the following physical properties:

a) crystallization rate> 90 seconds;

b) crystal melting temperature = 49 ⁰ C;

c) limit modulus = 38.7 kg / cm;

d) limit elongation = 15%

e) modulus at 400 % elongation * 49.2 kg / cm ² ;

f) tensile strength = 23.2 kg / cm ² ;

g) elongation at break = 615 %

h) Graves tear test, PIT - 400;

i) Melt index, 8O ⁰ C (2160 g) = 2.

- 15 -

409822/0980

B e i s ρ i e 1

An adhesive was made by mixing the following components at room temperature:

Component parts

Polyurethane polymer with a high rate of crystallization and a hydroxyl content of 0.1%

(Desmocoll 400) 6.50

Polyurethane polymer with an average crystallization rate and a hydroxyl content of 0.1 % (Desmocoll KA 8029) 0.81

Acid-modified copolymer of vinyl chloride and vinyl acetate (81 % vinyl chloride, 2.4% maleic acid and 16.6 % vinyl acetate) (Vinylite VMCA) 11.58

Epoxy resin (Araldite 6O1O) ^1J 2.03

Low mole weight polyester resin (Krumbhaar 1979). 0.81

Solvent mixture (methyl ethyl

ketone, acetone and toluene) 69.15

Sand colored pigment mixture (51.25 % solids in solvent) 9.32

1)
'Araldite 6010 is a liquid, unmodified resin.

. - 16 409822/0980

It is characterized by the following physical property en:

a) Weight per epoxy - 182 - 196

b) Viscosity at 25 ^° C. >> 12,000 to 16,000 cps

c) Color (Gardner) = 3 max

d) Specific weight = 1.15 x 1.17.

4.32 parts of polymethylene polyphenyl isocyanate were added to 95.68 parts of the mixture shortly before use

The adhesive was used to bond a vinyl chloride film to a chipboard and according to Example 1 tested; the green strength in the heat was somewhat lower, the strength after aging (two hours, 24 hours and 36 hours) were equivalent to those of the adhesive of Example 1.

Example 4

An adhesive was made from the following ingredients: 8.41 parts Rucothane P250-2, 8.41 parts Vinylite VMOA, 2.10 parts Araldite Epoxy 7079, 15.77 parts white pigment (51.9 % solids in solvent), 0, 86 parts Cabosil M-5 (fumed silica with 99.3 % SiO _n , upper

p ■ <-

area 200 m / g, mean particle size 0.012 / μm) and 64.45 parts of a solvent mixture from ethyl ethyl ketone, Xylene, acetone and diethyl isobutyl ketone. Just before use, 4.3 parts of polymethylene polyphenyl isocyanate were added added to 95.7 parts of the above mixture.

- 17 -

409 8 2 27

The adhesive was used for sticking a vinyl chloride sheet used on a chipboard and tested according to Example 1; it had essentially the same green strength in the heat and the same strengths after aging as the adhesive from example 1.

Example 5

An adhesive was prepared from 8.0 parts of Desmocoll 400, 1.0 part of Desmocoll KA-8029, 10.0 parts Vinylite VKCA, 2.5 parts Araldite Epoxy 7097, 1.0 part Krumbhaar 1979, 1.43 parts Cäbosil M-5 and 76.07 parts' Solvent mixture of methyl ethyl ketone, acetone and Toluene.

95.6 parts of this mixture were added shortly before use 4.4 parts of polymethylene polyphenyl isocyanate were added.

The adhesive was used for sticking a vinyl chloride sheet used on a chipboard and tested according to Example 1; for the green strength in the warmth was found a value which was in the middle of the values for the adhesives according to Example 1 and Example 3, while the strength after aging (2 hours, 24 hours and 36 hours) corresponded to that of the preceding adhesives.

Example 6

An adhesive was made from 7.02 parts Desmocoll 400, 11.81 parts Vinylite VMGA, 1.24 parts each Araldite 7097 and Araldite 6010, 2.99 parts Foinrez ^Λ \

- 18 -

409822/09 80

5.46 parts of gold-colored pigment (52.11 % solids in the solvent), 1.08 parts of Gabosil M-5 and 69 »16 parts of a mixed solvent of toluene, methyl ethyl ketone, acetone and xylene.

1): Pomrez 50 is a polyester resin from

Glycol-A & ipat type. It has the following physical properties:

&) Hydroxyl number = 50-55;

b) acid number = 2.0 max;

c) water content (Karl Fischer), % = 0.07 max; ά) color (Gardner) = 2 max;

t) Viscosity (Brookfield Model LVF, Mr. 4 spindle, 12 rev / min) at 25 ⁰ G = 17,000 - 22,000 eps

f) Specific weight at 25 ° C - 1.18 - 1.20

g) Appearance clear

_{Shortly before use, 3 t} 0i parts of polymethylene polyphenyl isocyanate were added to 9 & 99 parts of the mixture.

Part of the adhesive was used to stick a vinyl chloride sheet to a chipboard and was tested according to Example 1; the green strength in 4er heat was somewhat lower, while the strength values after aging were the same as those obtained in Example 1.

Another part of the adhesive was used to stick a vinyl chloride sheet to an aluminum sheet. 3 The laminate had about the same green strength in the Heat as indicated in Example 1 and the film was at

- 19 409822/0980

20 to 35% cracked in the peel test at 90 ° and 35 to 35% in the peel test at 180 °, the test having been carried out after aging for 2 hours. When the test was carried out on adhesive bonds that were 24 hours old, the film tore 100 % both in the 90 ° test and in the 180 ° test. With the above adhesive, attempts were also made to glue acrylic foils, polyethylene foils and acrylonitrile-butadiene-styrene foils onto substrates made of chipboard, paper, plywood, hard cardboard, lead, tin, aluminum and nickel. Both the green strength in the heat and the strength of the bonds after aging significantly exceeded the currently commercially available adhesives.

PATENT CLAIMS:

409822/0980

Claims (7)

PATENT CLAIMS l) Adhesives containing: (A) an isocyanate-curable adhesive solution composed of about 2 to 16 parts by weight of a linear polyurethane polymer with a hydroxyl content of at least 0.1 Jj; about 4 to 20 parts by weight of an acid-modified copolymer of vinyl chloride and vinyl acetate; about 1 to 5 parts by weight a polyepoxide; about 0.5 to 4 parts by weight of a hydroxyl group-bearing low molecular weight polyester resin; about 50 to 90 parts of solvent, optionally (B) 1 to 10 parts by weight of an isocyanate curing agent contains. 2) adhesive according to claim 1, characterized e k e η η - draws that the acid modified copoly mer! sat of vinyl chloride and vinyl acetate to about 75 to 88 - / j of vinyl chloride, consists of about 0.7 to 2.5% of an acid or an acid anhydride, and about 12 to 18% of vinyl acetate. 9 δ? 2 / Ci; ° 0 3) adhesive according to claim 1 or 2, characterized g e k e η η indicates that the polyester has a molecular weight of about 600 to about 3000 and a hydroxyl number of 40 to 350 has. 4) adhesive according to any one of claims 1 to 3, characterized in that the epoxy resin is a Is the condensation product of bisphenol-A and epichlorohydrin. 5) Adhesive according to one of claims 1 to 4, g e characterizing ei chn.e t by a content of a pigment and / or an agent for controlling viscosity. 6) Adhesive according to any one of claims 1 to 5, characterized in that the polyurethane polymer component a mixture of two or more linear polyurethane polymers with different crystallization rates is. 7) Use of the adhesive according to claim 1 to 6 for gluing plastic films, in particular polyvinyl chloride films on cellulosic or cellulosic or metallic substrates. 822/0980