DE1594269A1 - hot melt adhesive - Google Patents

Description

The invention relates to hot melt adhesives. she refers in particular to hot melt adhesives that can be made from inexpensive materials and have excellent warfare properties and on one process to achieve the better creep properties

Hot melt adhesives only give a bond through Cooling «which is to be distinguished from crosslinking or other chemical reactions., Before heating, the hot-

009886/2047

schmeXzklebatoffe feete substances schüttfähi ^ or ale tablets for ease of handling can be manufactured, NaOH heating melt the Hei0schraelzklebstoffe and flow freely for application to a 3ubstrat _o Since HeiQschmelzklebstoffe to the invention as to tend thermoplastic solidifying in the heat and they are melted again can, they can first be applied to a substrate and can later be melted again to form a hot melt bond with another substrate "

Hot melt adhesives are used for bonding wood, paper, plastics, textiles and other materials used "Bin special Anwendungezweig is the production of corrugated board" Heiflschmelzen used for the production of corrugated board, must have high bond strength under conditions as StoQbeanspruohung, high humidity and have extreme temperatures that can occur during transport and storage “There are also special requirements with regard to the melting point, the wetting side, the initial tack, the setting * or hardening time, the pot life and general handling properties on automatic corrugated paper soles.

Ee is already a cheaper hot melt adhesive with a high Efficiency has been suggested to get that can be that one is a hydrocarbon-aldehyde resin

BAD ORiGfNAL

009886/2047

(Pormolite resin) with one. Mixed polymer of ethylene and Vinyl acetate mixed.

These dimensions have excellent properties for use in joining materials, especially Paper "■ It has been shown that these masses can be used on corrugated paper machines, those for use for hot-melt adhesives Modified other hot melt adhesives regarding their behavior in the corrugating machine and ^ the corrugated paper made with it survived.

Standard tests on corrugated cardboard with a double top layer, made from molded resin and ethylene-vinyl acetate copolymers and comparative approaches with double-layer cardboard using ν η conventional adhesive Starch-based and the more expensive glue based on starch-resorcinol showed that corrugated cardboard can help of the new hot melt adhesives have been produced, better or at least equivalent to the usual corrugated cardboard using starch-based or resorcinol-starch-based adhesives In almost all properties, Bs is commonly believed to be corrugated cardboard made with HeiQechnelzklebetoffen, better -desired, than corrugated cardboard of the usual kind.

Corrugated cardboard _t made with hot-melt adhesive based on Pormolite-Harζ and ethylene-vinyl acetate mixed polymer

009886/2047 '. Bathroom original

has been shown to have certain drawbacks as regards their creeping properties o "The creeping properties can be define as the tendency that the woolen yarn unfl the Cover layers move parallel to the bond plane "when a shear force is exerted on the bond"

If the bond is tested for its creep properties by the method described below, it preferably has less than 5 f · creep properties in 24 * hours at 1.76 kg / cm ^2. (25 Ραβ, Ι.) And 60 ° C (T4O It has been found that hot-melt adhesives, which are only mixtures of a Foraolite resin and a Xthyler.-vinyl acetate copolymer, soothe iron under these conditions.

It is an object of the present invention to provide a hot whipped adhesive to produce all the desired properties of the Ponaolite resin and ethylene-vinyl acetate mixed polymer mixture possesses, however, its creep properties as VQllatendr ^ satisfactory in the production of corrugated paper suitable for all commercial purposes can apply.

It is a further object of the invention to provide a method Improving the creep properties of hot melt adhesives to specify.

Another abandonment of invention is to create a new hot «

009 886/20 4 7 bad original

to indicate hot melt adhesive «

According to the invention, the creep properties are improved by preparing a homogeneous mixture containing 25 to 65 parts by weight of ethylene-vinyl acetate polymer _s 30 to 65 parts by weight of aromatic carbon-aldehyde resin and 5 to 30 parts by weight of crystalline high-melting wax. The hot melt adhesives according to the invention preferably contain 35 to 60 parts by weight of ethylene vinyl acetate polymer, 30 to 45 parts by weight of aromatic hydrocarbon-aldehyde resin and 10 to 25 parts by weight of crystalline high-melting wax "

The production of ethylene-vinyl acetate copolymers is generally known. Processes are described, for example, in US Pat. No. 2,200,429 and Canadian Pat. No. 657,977. For this purpose, a mixture of ethylene and vinyl acetate with the aid of a radical catalyst such as oxygen is generally used or an organic peroxide in a _ 'pressure of 100 to 200 atmospheres and a temperature misohpolymerislert Iron 150 to 250 ⁰ C and ο isolated the polymer, the proportion of vinyl acetate in the resin does not seem to be crucial for the present purposes. Copolymers containing 17 to 35 percent by weight of vinyl acetate are suitable for compositions with improved creep properties = ethylene-vinyl acetate copolymers containing 17 to 30 percent by weight of vinyl acetate are preferably used.

00988 6/204 7 bad or.g.nal

The ethylene-vinyl acetate polymer can also be characterized by a softening point according to the ring and ball method of 82 to 20O ⁰ C (180 - 39O ⁰ P) and a natural quality at 30 ⁰ C of 0 ₉ 54 to 1, 05 get rid of »

The ethylene-vinyl acetate Miaohpolyaerieate used here are available commercially under the Beseiohnungen * 51vax "from the E" I · OuPont de Nenoure & Co., Bigenohaften of some epasial Elvax compounds including those) that have been used in the examples nan in the following table Io

ORIGINAL

00SS8S / 2047

Tabel!

Grade

Settmels ~ index 1)

i> vinyl acetate

Natural Viakoei

act 2 *

Density. / 5)

Refractive Index 25 "D

Softening! Point *'

BLVAX BLVAX BLVAX BLVAX BLVAX BLVAX ELVAX BLVAJC BLVAX BLVAX BLVAX

150 210 220 240 250 260 310 350 360 420 460

28 470 175

28

18th

465

22 2.4 175 2.9

0 «78 0.59 0.63 0.78 0.85 0.94 0.54 0.84 1.05 0.54 0.98 0.957
0.951
0.949
0.951
0.951
0.954
0.949
0.947
0.950
0.937

1 482 1.488 1,485 1,485 1.485 1,485 1o486 1,489 1,401 1.492 U 493

(240) (180) (190) (250) (280) (310) (190) (280) (370) (210) (390)

116

82

88

121

138

154

88

138

188

99

199

1) g./iO Kin. (ASTH S 1238 codified

2) at 30 ⁰ C. (0.25 g./iOO Bl. Toluene).

3) at 23 * 0. (ASTM Β 1505),

4) Hing and ball method ⁰ C

(ASTM E 28).

Aromatic hydrocarbon-aldehyde resins are known. Their preparation is described in the patent literature, t, Bo in the USA patents 1,827,538 and 2,992,206 and in the literature, see B. von Walker, Formaldehyde, 2nd edition, Rheinhold Publishing Company, New York, 1960, Pages 342 345.

Typical starting materials for the Tormolite reaction are aromatic hydrocarbon fractions that boil in the range from about 93 to 50 ⁰ C (200 - 950 °?) And are derived from petroleum refining rooms, such as cracked fractions, cycle structures, hydroforming bottoms, Fuel oil, single-use distillate fractions and pure aromatic fractions. They bsi the katalytisehen cracking resulting Gaeöifraktion, the "wipe about 232 and about 343 ⁰ C (450 - 65O ⁰ P) boiling and contains from 15 to 50 4 aromatic hydrocarbons, is a particularly preferred Auegangematerialο

Suitable pure aromatic hydrocarbons are see Β Bensol, alkylbftole, naphthalene »alkylnaphthalene, hydrogenated Naphthalenes or mixtures of such pure aromatic hydrocarbons. Binary special aromatic hydrocarbons are benzene, toluene, ethylbeneol, diethylbeneol, laphthalene, alpha-methylnaphthalene, beta-methylnaphthalene, Xthylnaphthalene, tetralin and. like that. ·

Suitable aldehydes are formaldehyde and materials that

009886/2047 ^ßAD

Formaldehyde result under the reaction conditions, such as Formalin, Paraformaldehyde, Trioxymethylene and Trioxane »Von In this group, formaldehyde and paraforalaldehyde are preferred because they are readily available and easy to calibrate let handle. Other aldehydes, such as acetaldehyde »propionaldehyde and butyraldehyde can be used. The aldehyde is absorbed in amounts of 1 to 30 percent by weight the aromatic hydrocarbons used in the reaction mixture " r ■; ■■ '. ■.'

Many catalysts have been used for the Pormolite reaction, see B «HgSO., HP, formic acid, phosphoric acid, BP- ₉ metal chlorides and other acidic catalysts. Sulfuric acid or B? ,, in the presence of acetic acid is preferred. Acetic acid acts as a modifier for sulfuric acid or B?,. Acetic acid seems to be the source of the acetate groups which can be found manohoally in the molecular structure of the Pormolite Harses. |

In a typical approach, 102.45 kg (226 pounds) of catalytic gas *! with a boiling range of 231 to 30O ⁰ C (448-572 ⁰ P) and a content of aromatics 47t3 4 (gel) and 6.32 kg (14 pounds) paraformaldehyde in a 13.2 1 (50 gallon), glass- given a lined reactor, which was provided with an agitator «. The mixture was to 88 - heated 110 ⁰ O (190 -23O ⁰ P).

009886/2047

This was followed by 18 pounds of 16 weight percent Sulfuric acid slowly iu 24.9 kg (55 pounds) Blsesslg with stirring and then the acid became too slow Poured into the rejection vessel while stirring.

Bas reaction mixture was about 30 Hinuten at 88-110 ⁰ C - stirred (190 23O ⁰ P). A closed system ▼ was used and the pressure slowly increased to about 3.25 to 3.32 kg / cm ² (32-33 p

The heating was interrupted, the acid layer was removed by settling, and the reaction products were pumped hot into a Waeeerwaechvorrichtung. Me products were washed four times. The water was removed by letting it dry and the reaction product was distilled in vacuo. The hard resin obtained was 13.92 kg (30.7 pounds). This corresponds to a bottoms fraction boiling above 260 ⁰ C / 1 mm Hg (500 ⁰ F) boiling. Bas material has a melting point by the ring and ball method of 105 ⁰ C. This Hars and other resins similarly prepared were analyzed for acetate. Br was about 0.1 to about 1.0 acetate groups per molecule of? Orxolite resin. The analysis was carried out with the aid of the saponification steel and with the infrared spectra.

The distillation of the product was carried out at 10 to 23O ⁰ C and Hg: it was found that the resin contained no acetate groups. Bio presence or absence of remaining

SAD ORIGINAL

009886/2047

Acetate groups In the Formolite-Har2 is of no importance for the purpose of the present invention.

Hard Marse with a swing point according to the ring and ball method of 70 Me 150 ⁰ C _1, preferably from 90 to 140 ⁰ C «are suitable · aromatic hydrocarbon-aldehyde components ·

. The Formula Hars used for the present invention can be characterized by certain properties in hexane. The solubility properties are represented as a fraction insoluble in hexane at room temperature (25 ° C.), a ^{fraction insoluble in hexane in the cold (0} ° C.) and a fraction soluble in hexane in the cold. Such properties are quite useful in the case of aromatic hydrocarbon-aldehyde hareses and a methylene-vinyl acetate-kiaeh polymer, since compatibility factors swisohen the bar and the seam polymer depending on the ßifiehfeprostnt at room temperature insoluble ffraketat- a tioninylacetatio to the weight proof in which ethylene- ¥ inylaeetat-Mlsohpolyaer can occur.

It has become more and more popular that through the addition of the critical component of the problem with regard to the compatibility is overcome and the oolite-haree among others. of their HexanlÖsliohkelt are compatible with Xthylene vinyl acetate sheet polymers without restriction

009886/2047

with regard to the amount of vinyl acetate present therein, to the extent that mixtures thereof according to the present invention. Invention are homogeneous mixtures that do not separate when left standing in the Hitse.

The wax used to provide good creep properties according to the invention is a component of the hot melt adhesives according to the invention: it is a highly meltable crystalline wax that is incompatible with the other components of the hot melt adhesive to the extent that macro pockets of the crystal when it cools down. form llnität · 2s has been found that suitable waxes, for example aikrokrietalline and paraffin waxes of petroleum are also synthetic waxes and natural waxes with a Schetltpunkt of at least 66 ⁰ C (1 5O ⁰ P) and in particular of at least 71 ⁰ C (160 °? ). The melting points of such waxes are generally in the range 66-107 ⁰ C (150 ⁰ F --85O), preferably in the range 71-93 ⁰ C (160-200 °?).

Suitable synthetic waxes are those made by the Piecfeer-Tropech process. Other suitable synthetic ingredients are _{, for} example, the amines of hydrogenated fallow fats, metaterphenyl and the ketones of long-chain fatty acids such as behenone and the like.

Suitable «, natural waxes are Karnauba, Montan, Ourioury,

00 9886/20 4 7

Shellac, sugar cane (refined wax), raffla, esparto guard and the same.

In addition to the appropriate melting point, the of good creep properties for the hot melt adhesives according to the invention used waxes insoluble in water “The wax component can be a single wax or a Mixture of different suitable waxes.

The hot melt adhesive is prepared by mixing ingredients at -the einer'Temperatur 93-204 ° C (200-400 ⁰ P) prepared "preferential catfish is applied the lowest temperature that leads to an adequate softening of all the components. This prevents unnecessary oxidation of the mass and is particularly economical. In the present Pail temperatures in the range 107-163 ⁰ C (225 - 325 °) is preferred. Usually, the mixing at about 146 ° C (295 ⁰ P) is performed.

Mixing can be done in any suitable manner. Am Satisfactory mixing can be easily achieved in a heated one Sigma plate type mixers accomplish the mixing continues until the adhesive mass is homogeneous.

When applied to a surface, the adhesive is ^{heated to a temperature of 121 to 234 0} C (250-45O ° P). In general, the lowest temperature which the

00.9886 / 204 7

desired viscosity generated, and for the application in question of the hot melt adhesive is suitable applied.

The hot melt adhesives can with regard to their suitability can be checked by two simple attempts.

The first is the tear bond attempt. The sample is cut from a 22.7 kg (50 pound) Kraft paper into 1.3 x U cm (0.5 by 5.5 inch) strips. Each strip is provided on a single side for a length of 2.5 cm (1 inch) with an elnea 25.4 / Ji (1 hill) thick coating of hot melt adhesive toffee. Then two 2.5 χ 1.3 cm (1 χ 0 .5 inch) of adhesive surfaces were brewed and the adhesive surface was applied with 1.25 kg (2 3/4 pounds) of Bruok to remelt the hot-melt adhesive and form a bond. In the present case was a conventional electric hand iron on the adhesive placed Smile Friend and the heat applied, including the adhesive to 121-232 ⁰ C? (250 - 45O ⁰ F) to heat. The sample then consists of two layers of paper, which are connected to one another on their inner surfaces over a 2.5 1.3 ca (1 0.5 inch) area on a brew adjusted so that all of the adhesive has approximately the same viscosity when bonded.

The test is performed by touching the free volume of the

BATH ORIGINAL 009886/2047

one strip attached to a stationary clamp and the free end of the other strip attached to a cord *. The gessjite device is placed in a variable temperature cabinet which is kept at a constant temperature for each sample. When the train is in action, it looks perpendicular to the plane of connection with one. Speed of 11.43 on (4.5 in) per minute. ^l

i Bine lend of samples to a particular HeiQsGhnslsklebstoff were in Abstünden of about 3 ⁰ C (5 ⁰ F) aufwarte carried out until failure of the bond of the adhesive occurred. The temperature "at which the adhesive bond failed" was & Mfgeseicht »t and the fmserriS is set as the next preceding temperature. A special sample is conditioned for 10 minutes before the test at the test temperature, the present case is a laser cut of 54 ^e C (130 ⁰ P) aaachateri is preceded by a teapera « _Λ door voa 60 ⁰ C (140 ⁰ P). '

Up to now, hot-haired adhesive samples were also ^{tested at (-10 0} P), to check their brittleness at strict, low temperatures,

Zn this Pail were duplicate samples at 23.3 ⁰ C (-10 ⁰ P) checked "Sine sample was the Hela Yerbindungsversuch auage, as described at 23.3 ⁰ C (-10 °?), While

BATH

009888/2047

the other Prob "to a severe shock, and then the Versuoh at 23.3 ⁰ C (-10 ⁰ P) is suspended. Only if both samples result in a tear-open seal, ie failure of the bond to the substrate (in this Pail Kraft paper), a tear-open connection is indicated _o

The "broad test" is the creep test. This test "eats the properties of the hotmelt adhesive under a given load. The experiment is carried out in a ™ Earner old constant temperature at 60 ⁰ C (RO ⁰ F). Sine the HeiBechmelzklebetoffmaeee tablet having a diameter and a height of 1.3 em (O ₉ 5 inches) is placed on a platform in the chamber and applied to it a load of 1.76 kg / cm (25 psi) for 24 hours. The percent deformation is determined by measuring the change in the height of the tablet. iSine deformation of 10 4 is acceptable - less than 10 ^ is preferred *.

The following examples were carried out with mixing . of the cash registers and their auditing as indicated. Any hot melt adhesive mass contains 1 percent by weight butylated hydroxytoluene (BHT) as an antioxidant. Whenever it was wet SLvax is used as an xthylene-vinyl acetate copolymer “The properties of the various Blvax mixed polymers are in Table I above.

BAD ORiGiMAL

009886 / 20.47

Z 1

Table II (connection) ft 9 ^{10 11}

12th

U 15 16 17 18 19 20 21

HeiSeehnels-

kleoetoffmasaen . . .-: //. ■. ■■

Ic ethylene

Vinyl acetate *

Mixed polymer \

Ty ps BLVAX 150 150 150 150 150 260 260 260

40 40 40 40 40 40 40 260

26Q 260 550 360 560 360 460 260 260 260 260

40 40 40 40 40 40 40 40 40 40 40

2ο Aromatic "Kahlenwaaaerstoff-Farmaldehyd resin *) Erwei chungepunkt by the ring-ball method U ₃

(pe) _ ·., 'rJjt » ¹¹ I ^ o

Gewo parts

■ 3 ·. Wachaart **) - Melting point ©? -

9 W.

5T ~ 3T

- B.

30 106
39 39

106 106 39 39

39-39 39

- A AA »

39 -

A A

C.

- 193J193 193T- -

Gev.-parts

20th Sy 20 20 20 59 2'O

185

4. » Softening

point after the ring and ball

method QC- 90 94 93 94 94 110 118 95 98 Q6 100 98 100 104 - -

x) 1 GeWo-part aronatiachee Kohlenwaeeerat off-Poraaldehyd-Harz has been replaced with BBB antioxidants

VJachaarten: _a:: Mikrokriatallin -Erdöl; E.g .: paraffin oil; C _e : Piecher-Tropach-eynthetic; D ,: Carnauba - natural: E .: Dihenei-σ) coeylketon (Behenon): P ₃ s 18-Pentatriaconta- ^ ⁰ non (Stearonh

Table III
<* rttfimg of the cash registers * «· * · Λ · η ·. 2)

Examples -t sr ν 4 5 β 7 β 9 10 11 12 13 14 15 16 17 18 IQ gn

Teat the
Paper samples

• *

;, Tear open »

Connection ■

Type of

say the

Link '

ο in the vaser

ο QC 46 49 54.5 57 57 60 60 57 57 63 66.5 38 63 66.5 71 44 66.5 63 66 63.5

»Of 115 120 131 135 135 140 140 135 135 145 156 100 145 156 160 112 156 145 150 146

5? · ■ in * glue

⁰ C 49 51.5 57 60 60.5 63 63 60 60 66 71.5 42 66.5 70.5 66.5 46 71.5 66 69 66 op 120 125 135 140 141 145 145 "UO UO 150 161 108 151 159 165 115 161 150 155 150

o Art Sa's failure

^ I *) Wb fib fib fib fib fib fib Jib ffib Adh Wb Pib fib fib fib fib fib fib fib fib fib fib

2. Creep

'< Deforea- -., ■. .. '

ro tion at,

σ 60OC. ·

ο (UOOf) Scheele · 9.0 9.2 20 20 20 5.5 13 ² «? 2.5 1.7 2.8 2.0 1.6 0 _β 9 1ο4 2.7 3 «2 1.8

1 ν

>"^; fib * feeer vol

Adb - adhesive <O

It can be seen from Examples T -5 that the use ▼ on hoohachmelsenden crystalline waxes according to the teaching of the present invention the quality of a sieralich effective Helflsohmelsklebetoffee improved It is not without it see why a guard with a melting point below the ring and ball method Softening point «the other main ingredient · the properties which are a function of temperature. Me better results can be due to the intolerance and crystallinity of the high-melting waxes and not up the high melting point alone can be attributed to the incompatibility of the waxes with the ethylene vinyl acetate formulations When cooling, small pockets of the Krletallinltat (Macrotaechen) in the bond, the one high sehmeis point and sufficiently uniform b «w. smoothly at the low applied concentration let to a resistance to creep and a reaming to result, which is required for corrugated cardboard. Although the wax is incompatible with cooling, the hot ohms system is called homogeneous solution, which when standing in the Hitse does not secrete. The Heiesehmelsmasae can be up to iur solid form and be molten again later: even then it still remains homogeneous, since the ttaehstasohen ao are small.

From Examples 12 and 16 it can be seen that only the use of a crystalline, chachmelsend

009886 / 20A7 _BAD

Whats Susannen old the ethylene vinyl acetate Miechpolymer does not give a satisfactory bond.

The veglaesen of wax does not lead in the same way su a satisfactory connection, since the war characteristics become unacceptable.

The examples given here serve only to illustrate and not to restrict the invention Examples serve in particular for the person skilled in the art only as guidelines, in order to help the knowledge given here for old Select the necessary conditions for the respective purpose.

Claims

• ORIGINAL BATHROOM

009 886/2 0 U 7

Claims (2)

1. Thermoplastic hot melt adhesive, which is a mixture of 35 to 60 parts by weight of an ethylene-vinyl acetate mixed polymer with 17 to 30 percent by weight of vinyl acetate and 30 to 45 parts by weight of an aromatic hydrocarbon-aldehyde resin with a melting point of 70 to 150 ⁰ C contains, according to main patent S 97 435 IVc / 22i, thereby g β k e η η ze 1 ch η β t that it additionally has 10 to 25 parts by weight of a crystalline wax with a melting point of at least 65 ^° C. 2 adhesive α according to claim 1, is characterized without marked in t that the guard has a melting point of 65-105 ⁰ C. 3 # adhesive NaOH to claim 1 or 2, characterized ke g β η η i ze et oh η that the wax has a melting point of 70 to 95 ⁰ C, in particular from 7O ⁰ C possesses. 4 »Adhesive according to claims 1 to 3» characterized by g β k e η η that the crystalline wax is a microcrystalline mineral oil or a synthetic wax, in particular Diheneicosyl ketone or 18-pentatriacontanone. 009886/2047 5 * Adhesive according to claims 1 to 3 »characterized by g β k e η η that the crystalline wax is a natural wax, especially carnauba wax. 6, adhesive according to claims 1 to 5, characterized in that the aromatic hydrocarbon-aldehyde resin has a softening point of 90 to HO ⁰ C determined by the ring and ball method » BAD ORiGiNAL 009886/2047