FI57777C - LIMTRAOD - Google Patents

Description

I * 1 - »* -—'-" I rRi NOTICE OF PUBLICATION

4BTa [B] (11) UTLÄCGNINCSSKR1FT 5 7 7 7 7 C (45) Patent granted 10 10 I960 Patent meddelat (S1) ICv.lk?/lnt.a.3 C 09 J 7/02 ENGLISH I —EN N LAN D (21) F «** ttlhtUiwi · - PiMiitmBkiiliif 15 ^ 6/71 (22) H * k * ml * cloud» - Ameknlniadag 03.06.71 (23) AlkuplWI — GlM | h «tadag 03.06.71 (41) Tullut JuUdMkti - BIMt offuntlig 01 + .12 71

Patent * and the National Board of Registration / 44s NthtivUulp «no« i Ja kuL | ulkml * un pvm. -

Patent and registration authorities AraMon utlagd och utUkriften pubUcund 30.06.80 (32) (33) (31) Pjryistty «uo) l« u * —Bugird prtorit «t 03.06.70 22.03-71 Engl anti-England (GB) 26891 / 70, 751 ^ / 71 (71) CPC International Inc., International Plaza, Englewood Cliffs,

New Jersey, USA (72) George Wilson, Liverpool, England-England (GB) (7 * 0 Oy Kolster Ab (5 * 0 Glue - Limträd

The invention relates to an adhesive yarn comprising a core which is a natural fiber or a synthetic fiber coated with a hot melt adhesive. Such yarns have a special use in gluing together two layers of web material, e.g. two sheets of paper or woven fabric or non-woven fabric, whereby they are joined together by gluing along one or more lines using glue yarns.

According to FI patent 5 * + 153, a method is provided for joining two continuous layers of web material together, whereby (a) an adhesive yarn comprising a core coated with hot melt adhesive is drawn from a feed stock, (b) an adhesive yarn is placed between two layers of web material, (c) two layers of web material are continuously and pressurized while softening the coating of said adhesive yarn.

According to another embodiment of the FI patent, there is provided a method of joining a web material, the method comprising the steps of: (i) continuously placing an adhesive yarn comprising a hot melt coated core next to a continuous layer of flexible web material, 57777 thereby gluing the adhesive yarn to the web material; treating the layer of web material parallel to the chip to separate lengths, (iii) folding each length along the line so that the surfaces on which the adhesive yarn is facing each other, and (iv) pressurizing each folded length while softening the adhesive yarn coating so that it adheres to each other said lengths on opposite sides of the fold line.

This invention relates to adhesive yarns suitable for use in these methods.

The object of the present invention is to provide an adhesive yarn suitable for joining webs, which has certain properties for carrying out this.

The adhesive yarn used in the application of these methods must satisfy a number of different characteristics in order to obtain a suitable result. The adhesive and core must be suitably flexible at normal temperatures to avoid excessive changes in the properties of the web material after gluing. The core must be strong enough to allow the wire to be pulled through the device with which the hot melt adhesive is applied and to allow the adhesive wire to be pulled out of the braked spool during gluing.

The adhesive coating must have some surface lubricating properties so that it can be pulled through the guide without appreciable surface damage. A particular requirement is that the adhesive coating must have good "hot tack", as the method of the invention is based on the use of an adhesive yarn whose coating is very viscous when hot, whereas at normal low temperature the adhesive provides a strong strong bond between web materials. It is also recommended that the viscosity of the adhesive coating remain in the high viscosity range over a reasonably wide temperature range, as this makes the gluing easier to control. The temperature at which the adhesive coating has the required viscosity can vary considerably depending on the operation for which the wire may be used. The adhesive yarn can thus be added to the products used at a temperature as low as T0 ° C, but when the product may be washed, the minimum application temperature required for the adhesive-gala must be at least 110 ° C, most preferably 120-135 ° C.

The invention is characterized in that the denier of the core is 50-1000 and the strength is at least 0.9 g / denier at 65% humidity and 20 ° C, the hot melt adhesive is used in an amount of 0.2-0.5 g / m, said the coating is a mixture having the following composition: 57777 as follows: ethylene-vinyl acetate copolymer 15-50% wax 0-20% tackifying resin 35-65% adhesive news inhibitor 0-5% antioxidant 0.1-2% pigment or filler 0-10% wherein the percentages are calculated from the weight of the adhesive, and the adhesive mixture softens to a viscosity value of less than 500 P at a temperature of 100-200 ° C.

The core of the adhesive yarn can be any material that does not substantially stretch in use and is stable at the temperatures to which it is heated, for example, polyester, polyamide, cotton, rayon, glass, and wadding. The core strength should preferably be at least 0.9 g / denier at 65% humidity and 20 ° C. The denier of the heart is most preferably 50-3000, and is often less than 1000, e.g. between 100-125. Generally, fine-core yarns are used to bond thin or open-woven materials, while coarser-core yarns are used to bond thicker fabrics or impermeable materials, such as plastic sheets.

The core is coated with a layer of hot melt adhesive. Preferably the core is coated with 0.02-2.0 g, preferably 0.05-0.5 g of hot melt adhesive per meter. In general, fine hearts are coated with a thin layer of glue and vice versa. Thus, typical adhesive coatings may weigh 0.0U g / m 2 for 125 denier cores and 0.08 g / m 2 for 250 denier cores. However, increasing the thickness of the adhesive coating on the core not only increases the bonding strength of the yarn but also increases the insulation that protects the core from thermal damage when the yarn is heated to soften the adhesive. Thus, the thicker coating allows for greater strength under heating conditions, and is highly preferred when the wire is to be heated to higher temperatures, e.g., to incorporate impermeable materials.

An important factor in gluing is the viscosity of the hot melt adhesive during the time when the two layers of web material and the adhesive wire between them are pressurized. The ideal viscosity depends on the nature of the substances and the following guidelines may be considered as recommended limits in any particular case: (1) Paper (non-fluffy). Viscosity as low as 6 poise at the interface.

(2) Paper (porous) - when penetration is required - as in (l) above, - When penetration is not required - 200-2000 poise 57777 k or higher, preferably 500-1000 poise.

(3) Open structure (very porous), such as woven fabrics and nonwovens. A very high viscosity is used - about 500-U0O0 poise, most preferably 1500-2000 poise, together with relatively low connection pressures and longer compression times.

{k) Non-porous materials such as polyethylenes. Use a lightly coated yarn - 0.1 g of glue per meter of yarn - to obtain a surface-sticky connection where deformation of the polyethylene film is kept to a minimum. To achieve good bond strengths, a coating weight of 0.2 g of adhesive per meter of wire or even higher weights is required. These provide high joint strength, but also cause greater distortion. The viscosity of the adhesive at the interface should be greater than 50 poise and most preferably greater than 200 poise.

(5) When a non-tear film with a high tear strength and a high surface tear strength is used, a small penetration of the adhesive is necessary in order to obtain a strong joint. This is best achieved by using adhesive coatings having a connection viscosity of more than 200 poise and most preferably more than 1000 poise while using high pressures on press rolls and an adhesive coating weight of more than 0.2 g of adhesive per meter of wire.

The temperature of the adhesive at the time of application depends on the desired viscosity at this point and the composition of the adhesive used. For a particular connection, there is a temperature range to which the hot melt adhesive can be applied. If the gluing temperature is too low, then either the connection formed is too weak or no connection is formed. If the temperature is too high, then either an excess flow of glue or thermal decomposition of the wire or material will occur. Suitable temperatures are best determined experimentally in each case.

In the gluing operation under normal conditions, the cooling of the hot melt adhesive after connection takes place so rapidly that the adhesion takes place almost immediately.

In order to better understand this method of manufacturing an adhesive yarn according to the invention, reference is made to the accompanying drawing. The drawing shows hot melt adhesive 10 stored in granular form in a feeder 11 from which it is drawn into a heated extruder 12 driven by a two horsepower DC Vari-Speed 20: 1 drive motor 13. Six wires 1U are drawn from six spools 15 into a heated extruder 12 from where they come 16 coated with hot melt adhesive. The coated wires are drawn through a water-cooled heat exchanger 17 where the hot melt adhesive coating solidifies and is developed in half 18 in a six-position hydraulic developer 19. The speed of the hydraulic developer 19 is electrically tied to the speed of the drive motor 13 so that the coating weight can be adjusted.

The hot melt adhesive generally comprises a mixture of a thin film forming polymer, a resinous resin and optionally a wax. The mixture is formed so that it softens to the desired viscosity value according to the application at a temperature of T0-200 ° C, preferably 100-150 ° C and most preferably 120-130 ° C.

The thin film-forming polymer used in the hot melt adhesive coating is preferably an ethylene-vinyl acetate copolymer, exemplified by the polymers sold by Du Pont under the trademark Elvax and I.C.I. under the trademark E.V.A. Other suitable polymers include hydroxy-modified ethylene-vinyl acetate copolymers and thin film-forming polyamide resins. Such polymers form a strong and secure bond with many different ramamates. The wax acts as a filler for the polymer and also changes the viscosity of the mixture.

A wide variety of resins can be used as the tackifying resin. Examples of tackifying resins are polyamides, hydrogenated resins, resin esters, polyterpene resins, oC-methylstyrene / vinyltoluene copolymers and chlorinated diphenyls.

If the adhesive coating mixture softens at low temperatures, it is usually desirable to include an anti-adhesive in the mixture to prevent the adjacent turns of the adhesive yarn from sticking together after the yarn has been wound on a bobbin. The anti-gluing agent can also act as a lubricant, giving the adhesive yarn a self-lubricating property when the yarn is pulled through the guides, as mentioned above. A suitable substance is an amide wax sold by Armor Hess under the trademark ARMIT HT.

The composition of the hot melt adhesive coating can vary within the following limits:

15 to 50% (preferably 25 to 0%) of ethylene-vinyl acetate copolymer

Wax 0-20% (preferably 2-10%)

Sticky resin 35-65% (preferably 105-60%)

Up to 5% anti-adhesive (preferably 0.5 ~ 2%)

Antioxidant 0.1-2%

Pigment or filler up to 10% 6 57777

The following are eight examples of hot melt adhesive compositions that can be used to coat a yarn by any desired method, for example, by holding the hot melt in a bath with a nozzle at the bottom and passing the yarn down through the melt and nozzle. All percentages are by weight.

Example 1

Elvax 250 © 25%

El butter 210® 7%

Staybelite resin 1 * 7%

Microcrystalline wax (m.p. 78 ° C) 12% Filler 8%

Antioxidant 0.5 JK

"Armid HT" 0.5%

Example 2 "Versamid 930" 35% "Versamid 900" 5%

Arochlor 5U6o® 1 * 0% Filler 8%

Paraffin wax (m.p. 77 ° C) 11%

Antioxidant 0.5% "Armid HT" 0.5%

Example 3 EVA 28-25® 8% EVA 28-20® 25%

Piccotex 100® 55%

Microcrystal wax (m.p. 78 ° C) 10% "Scars HT" 1%

Antioxidant 1%

Example U

ELVAX 260® 10% ELVAX 250® 10% ELV0N 20B® 5%

Stayhelite Ester 10® 55%

Microcrystalline wax (m.p. 78 ° C) 10% "Scars HT" Ί%

Antioxidant 1% Filler 8% 57777 τ

Example 5 ELVAX 1 + 20® 25%

Polytylene 15%

Piccotex LC resin® 1 + 0%

Microcrystalline wax (m.p. T8 ° C) 10% "Scars HT" 1%

Antioxidant 1% Filler 8%

Example 6 ELVAX 350® 30% ELVAX 310® 5% NIREZ 1100® volume%

Microcrystalline wax (m.p. T8 ° C) 15% "Scars HT" 1%

Antioxidant 1%

Example 7 EVA 28-05® 25% EVA 28-20® 10%

Arochor 5 ^ 60® 58%

Microcrystalline wax (m.p. 78 ° C) 1+% "Scars HT" 1%

Antioxidant 2%

Example 8 EVA 28-05® 30% EVA 18-02 ® 5% ACP-8 polyethylene® 5%

Arochlor 5 ^ 60® 58% "Armid HT" 2%

Elvax® grades of ethylene-vinyl acetate copolymer are sold by Du Pont and are explained below: 8

Herring

Elvax ^ quality% vinyl acetate Melt index (1) 210 27-29 3U0-1 + 70 250 27-29 12-18 26Ο 27-29 5-7 310 2U-26 335-U65 350 2Ϊ + -26 16-22 ^ 20 17 -19 125-175 (1) Melt Index - g / 10 min (ASTM D1238 modified) "Versamid 930 and 900" are polyamide resins and are explained as follows: "Versamid" quality Melting point ° C (a) Amine value 900 180-190 3 930 105 -115 3

Melting point (a) ASTM 12U0

EVA® grades of ethylene-vinyl acetate copolymer are sold by I.C.I. and are explained as follows: EVA® grade Vinyl acetate% Melt Index 28-25 28 25 28-20 28 20

Staybe lit e ^ resin is a hydrogenated resin sold by Hercules.

Arochlor ® resins are chlorinated diphenyls.

Piccotex 100® is an ot-methylstyrene / vinyltoluene copolymer with a melting point of 100 ° C, and Piccotex LC® resin is a similar substance. Both are sold by the Pennsylvania Industrial Chemical Corporation.

Elvon 20B® is a hydroxy-modified ethylene / vinyl acetate copolymer sold by Du Pont.

The polyethylene used in Example 5 has a softening point of 116 ° C and a viscosity at 10 ° C of 350 cP.

Nirez 1100® is a polyterpene resin with a melting point of 100 ° C, sold by Tenneco Chemical.

Claims (3)

9 57777 An adhesive yarn comprising a core of natural fiber or synthetic fiber coated with a hot melt adhesive, characterized in that the core has a denier of 50 to 1000 and a strength of at least 0.9 g / denier at a humidity of 65 # and a temperature of 20 ° In C, a hot melt adhesive is used in an amount of 0.2-0.5 g / m, said coating is a mixture having the following composition: ethylene-vinyl acetate copolymer 15-50% wax 0-20% tackifying resin 35-65% anti-adhesive 0- 5% antioxidant 0.1-2% pigment or filler 0-10% the percentages are calculated on the weight of the adhesive, and the adhesive mixture softens to a viscosity value below 500 P at a temperature of 100-200 ° C. Adhesive yarn according to Claim 1, characterized in that the tackifying resin is polyamide, hydrogenated rosin, rosin ester, polyterpene resin, ormethylstyrene / vinyltoluene copolymer or chlorinated diphenyl. Adhesive yarn according to Claim 1 or 2, characterized in that the composition of the adhesive coating is as follows: ethylene-vinyl acetate copolymer 25-Uo% wax 2-10% tackifying resin U5-60% anti-adhesive 0.5 ~ 2% anti-oxidant 0.1- 2% pigment or filler 0-10% where the percentages are based on the weight of the adhesive. Adhesive yarn according to one of the preceding claims, characterized in that the composition of the coating is selected such that the coating softens at a temperature of 120-130 ° C.