JPH06299043A - Conveyor belt produced from hot melt composition based on hydrogenated block copolymer derived from vinylaromatic compound and conjugated diene - Google Patents

Abstract

PURPOSE: To obtain a hot melt composition which when applied to a specified fabric can give a conveyor belt covered with a polymer layer on only one of the surfaces of the fabric by compounding a specified block copolymer, a non-aromatic plasticizing oil and a terminal block compatible resin.

CONSTITUTION: A hot melt composition suitable in the production of a conveyor belt is obtained by mixing (A) a block copolymer which is composed of at least two terminal poly(vinylaromatic) blocks and at least one internal poly(conjugated diene) block, in which at least 80% of the initial ethylenic unsaturations of the poly(conjugated) diene block have been hydrogenated, and which may be modified by grafting onto polar sites with (B) a non-aromatic plasticizing oil and (C) a terminal block compatible resin. By applying the above composition on a fabric having 5-25/cm of threads having a thickness of 20-300 μm in both the directions, a conveyor belt covered with a firmly adhered polymer layer on only one of the surfaces can be produced.

COPYRIGHT: (C)1994,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention is directed to a top portion derived from a hot melt composition based on a vinyl aromatic compound and a conjugated diene, especially a hydrogenated block copolymer of styrene and butadiene and / or isoprene, respectively. A conveyor belt having layers, a hot melt composition to be used, and a method for manufacturing said conveyor belt.

[0002]

BACKGROUND OF THE INVENTION Most conveyor belts for various applications are currently plasticized polyvinyl chloride (PVC) or polyurethane (TPU) with one or more polyester (PET) or polyamide (PA) fabrics as the support. ) Is manufactured in combination. The belts are mainly used in the food industry and business / service fields.

To date, the belts have been applied directly to the base fabric as plastisols in the case of PVC and as dusts in the case of polyurethanes.
ard process). .

In any case, the polymer sheet produced by melting in an oven at about 200 ° C. for a short time, usually less than 1 minute, is 2 N / mm or more, preferably 3 N / mm or more as measured by a T-type peel test. Adhere to the cloth with the force of.

However, the need for reuse of these belts, the optionally higher dust absorption and the limited use at low temperatures up to -40 ° C. has increased the need for alternative materials.

[0006]

SUMMARY OF THE INVENTION It is a first object of the present invention to provide an alternative conveyor belt as described above which can be completely regenerated without serious environmental impact due to the production of toxic by-products. .

More particularly, the first object of the present invention is to provide a polymer layer which, unlike the ones currently used, is adhered on only one side of the fabric with a sufficiently high force (ie greater than 2 N / mm). To provide an alternative conveyor belt as described above which is coated and which also exhibits lateral stability, ie stability perpendicular to the direction of product transport.

It will be appreciated that when using conventional coating methods such as extrusion coating or reverse roll coating, it is not possible to achieve this end even with compositions containing eg EPDM or TPU. .

As is generally known, in the case of conventional conveyor belts made from latex of SBR (Random Vinyl Aromatic / Conjugated Diene Rubber) and cloth, the threads of the cloth are preferably in order to achieve good adhesion. , For example resorcinol-formaldehyde latex.

Furthermore, it is self-evident that the conveyor belt containing the above SBR or EPDM must be heat-treated to bring it into its final form.

[0011]

As a result of extensive research and experimentation, the conveyor belt of interest, which is the subject of the present invention, has at least: (a) at least two terminal poly (vinylaromatic) blocks and at least one. Two internal poly (conjugated diene) blocks, wherein at least 80% of the original ethylenic unsaturation of said poly (conjugated diene) blocks has been selectively hydrogenated and optionally modified by grafting polar moieties. An optional block copolymer, (b) a non-aromatic plasticizing oil, and (c) a terminal block compatible resin in a hot melt composition in the range of 20 μ to 300 μ, preferably 100 μ to 300 μ. 5 to 25 threads / cm, preferably 10 to 20 threads / c in both directions
m, more preferably 15-18 / cm, that is, cloth 1
It was surprisingly found to be obtained by applying on a cloth having (15-18) x (15-18) books per cm ² .

The coating density of the hot melt composition of the conveyor belt according to the invention is in the range of 0.5 to ³ g / cm ² , preferably in the range of 1 to ² g / cm ² .

Another subject of the invention is suitable for the production of conveyor belts, comprising at least: (a) at least two terminal poly (vinylaromatic) blocks and at least one internal poly (conjugated diene) block, said At least 80% of the initial ethylenic unsaturation of the poly (conjugated diene) block is selectively hydrogenated, optionally a block copolymer modified by grafting polar moieties, (b) non- It will be appreciated that there is a hot melt composition comprising an aromatic plasticizing oil and (c) an endblock compatible resin.

The block copolymers found to be suitably applied are preferably linear triblock copolymers or multibranched (three or more branched) radial or star block copolymers, The blocks are each mainly derived from styrene and butadiene or isoprene.
The term "predominantly derived" means that the main monomer of each individual block may optionally be mixed with small amounts of another comonomer, and more particularly with small amounts of other block main monomers. To do.

Examples of vinyl aromatic monomers are styrene, α
-Methyl styrene, p-methyl styrene, m-methyl styrene, o-methyl styrene, pt-butyl styrene, dimethyl styrene, vinyl naphthalene, and mixtures thereof, and the conjugated diene is butadiene, isoprene, piperylene and mixtures thereof. And so on.

Of these monomers, styrene and butadiene or isoprene or mixtures thereof are preferred. The most preferred block copolymers are those containing only substantially pure poly (styrene) blocks and substantially pure poly (butadiene) or poly (isoprene) blocks.

Examples of the above block copolymers which may be suitably used are KRATON G block copolymers (KR
ATON is a trademark), more preferably KRATO
NG 1652 block copolymer is used.

The selectively hydrogenated block copolymers to be used as component (a) of the hot melt composition optionally comprise carboxylic acids or their derivatives, epoxy compounds, silane compounds, amines or amides. It may be modified by grafting a polar substance. Typical examples of block copolymers grafted with a derivative of an unsaturated acid are disclosed, for example, in US Pat. 4,007,3
11, US Patent No. 4,264,747, European Patent Application No. 0085115, 0173380, 02
Known from 15501, 0301665.

Preferably, the polar material is grafted onto the selectively hydrogenated poly (conjugated diene) block.
More preferably, unsaturated carboxylic acids or their esters or anhydrides are grafted onto the poly (conjugated diene) blocks.

Preferred examples of the above-mentioned grafting agent are maleic acid or anhydride thereof, fumaric acid or ester thereof, itaconic acid or ester or anhydride thereof, acrylic acid or methacrylic acid or ester of these acids, preferably acrylic acid. It is glycidyl. More preferably, maleic anhydride or acrylic acid ester is used. Examples of commercially available maleic anhydride grafted block copolymers are KRATON FG 1901 and FG.
It is 1921 X.

Mixtures of unmodified hydrogenated block copolymers and modified (preferably structurally related) hydrogenated block copolymers can be used as component (a).

It has been found that applying a mixture of functionalized and non-functionalized block copolymers gives even better adhesion, eg at least 4 N / mm.

In the above mixture, the weight ratio of the non-modified block copolymer component to the modified block copolymer component is 95.
/ 5 to 40/60, preferably 80/20 to 50/50
Can be changed within the range.

The molecular weight of the terminal block of the selectively hydrogenated block copolymer is usually 3,000 to 100,000.
0, preferably in the range of 5,000 to 20,000, and the apparent molecular weight of the internally selectively hydrogenated poly (conjugated diene) block is usually 10,000 to 300,
000, preferably in the range of 30,000 to 100,000. Precursors of poly (conjugated diene) blocks are usually 5 to 50 mol% based on the conjugated diene molecule, 1,
2 Contains vinyl groups of polymerization origin.

The complete block copolymers to be used according to the invention are usually 20 to 60% by weight, preferably 2
It contains from 5 to 40% by weight of bound vinyl aromatic compounds. The apparent molecular weight of the entire block copolymer is usually 2
30,000 to 350,000, preferably 40,000
Is in the range of up to 200,000.

Various plasticizing oils as component (b) are useful in the compositions to be used according to the present invention.

Plasticizing oils found to be useful include oils derived from petroleum, oligomers of olefins, low molecular weight polymers, and vegetable and animal oils and their derivatives.

Oils derived from petroleum which can be used are relatively high-boiling materials and contain small amounts, preferably less than 20% by weight of the oil, more preferably less than 15% by weight of aromatic hydrocarbons. No, most preferably the oil is completely non-aromatic. The oligomer has an average molecular weight of 350 to
Polypropylene, polybutene, having 10,000
It can be hydrogenated polyisoprene, hydrogenated polybutadiene, polypiperylene and piperylene-isoprene copolymers.

Animal and vegetable oils include glyceryl esters of conventional fatty acids and polymers thereof.

An example of a preferred paraffinic petroleum oil is 500
Primol having a molecular weight in the range of ˜6,000
352 (Primol is a trademark) and Napvis and Hy
vis ™ polyolefin. Preferably 100 to 200 parts by weight are used per 100 parts by weight of the block copolymer, more preferably 120 to 170 parts by weight per 100 parts by weight of the block copolymer.

As the component (c), various end block compatible resins are useful in the composition used according to the present invention.

Examples of the terminal poly (vinyl aromatic) block-modified resin include coumarone indene resin and polyphenylene ether, and more particularly poly (2,6-dimethyl-1,4-phenylene ether), polystyrene resin and vinyltoluene. Includes α-methylstyrene copolymer resins, polyindene resins or poly (methylindene) resins.

Examples of the above-mentioned commercially available resins are HERCURES
HM 100, ENDEX 160, KRISTALE
X F 120, KRISTALEX F 5140,
NEVCHEM NL 140 and PICCOTEX
120 (HERCURES, ENDEX, KRISTA
LEX, NEVCHEM and PICCOTEX are trademarks)
Is.

Preferably, 50 to 150 parts by weight, more preferably 75 to 150 parts by weight, per 100 parts by weight of the block copolymer.
125 parts by weight of the above end block modified resin are used.

Preferred modified resins are optionally substituted polystyrene resins and / or polyphenylene ethers. More preferably, substituted polystyrene and / or poly (2,6-dimethyl-1,4-phenylene ether) is used.

The starting cloth is made of polyester (PET or P
BT), polyamide, poly (ethylene), aramid,
It can be based on various synthetic or natural threads such as cotton, flax, of which polyester cloth is preferred.

More preferably, a PET cloth having long, straight and relatively thick (for example 300μ) yarns and filaments in the main direction and thinner (for example 100μ) wrinkled yarns and filaments in the longitudinal direction is used. To be done. The fabric threads or filaments may have been pretreated with resorcinol-formaldehyde latex. The above fabrics have been found to provide improved adhesion to vinyl aromatic / conjugated diene block polymer hot melt compositions.

It has further been found that PET fabrics containing cut filaments that impart a texture to the surface of the fabric provide the strongest adhesion compared to PET fabrics containing long (uncut) filaments.

The hot melt composition optionally contains, in addition to the three main components described above, stabilizers, fillers, colorants, slip agents and polyethylene, preferably LLDPE, polypropylene, ethylene-vinyl acetate copolymers and the like. It will be appreciated that it may include one or more auxiliaries such as additional thermoplastic polymers.

Stabilizers or antioxidants optionally used in accordance with the present invention include high molecular weight hindered phenols and polyfunctional phenols such as sulfur and / or phosphorus containing phenols. Hindered phenols are well known to those skilled in the art and can be characterized as phenolic compounds that "also contain sterically bulky radicals in close proximity to the phenolic hydroxyl groups." In particular, the t-butyl or t-amyl group is usually substituted on the benzene ring in at least one ortho position to the phenolic hydroxy group.

Typical examples of the above-mentioned stabilizers are SUMILIZ
Trademarks of ER and IRGANOX, such as SUMI
Commercially available as LIZER GM and IRGANOX 1010.

Inorganic and organic fillers which are familiar to the person skilled in the art can be used as additional auxiliaries. Examples of such fillers include calcium carbonate, aluminum silicate, clay, talc, titanium dioxide, bentonite,
Kaolin, barite, mica, silica, barium sulfate or mixtures thereof are included. Examples of preferred inorganic fillers are commercially available under the trademark MILLICARB.

Preferably, an amount of up to 80 parts by weight, preferably 50 to 70 parts by weight, of LLDPE per 100 parts by weight of the block copolymer is added to the hotmelt composition as an additional polymer component for further improvement in abrasion resistance. May be included.

Application of the hot melt composition to the fabric by a one step process method such as extrusion coating according to the present invention may result in greater penetration of the fabric due to the low melt viscosity (high melt flow rate) of the hot melt composition, It has been surprisingly found that the polymer composition can be adhered to fabrics, especially polyester fabrics, with very good forces of 4 N / mm or more, to obtain a conveyor belt that produces excellent 180 ° T-peel force. .

Also, the conveyor belts obtained according to the present invention appeared to exhibit excellent flexibility.

Another subject of the invention is the application of the hotmelt composition specified above to a fabric to form a one-sided coating layer having a thickness in the range 0.5 to 5 mm, preferably 1 to 3 mm. It will be understood that there is a method of manufacturing a conveyor belt, including:

It will be appreciated that the top of the solidified hot melt composition layer of the conveyor belt may be further coated with a layer providing improved abrasion resistance, for example of a sprayable epoxy or polyurethane system.

The application of this hot melt composition can be carried out by the usual application methods, and in particular by means of an extrusion coating process, which uses a three-roll take-up device for compressing the sheet and the fabric.

US Pat. No. Shot-tear resistant composite products are known from 4,623,574 each consisting of a network of reinforcing fibers coated with an elastomeric matrix material.

British Patent Application No. From 2181670,
Twisted filament yarn and spin yarn of synthetic fiber
Tubular lining materials for pipelines are known, which have a warp and a weft consisting of n n arn) and a coating of a mixture of polyethylene and ethylene-ethylene-butylene which penetrates the weave of the fabric.

However, no technical teaching, such as teaching the conveyor belt of the present invention, can be derived from the above patent specifications.

[0052]

EXAMPLES The present invention will be further described based on the following examples, but the scope of the present invention is not limited to these examples.

Example 1 100 parts by weight of KRATON G-1652 block copolymer were added, and the melt viscosity at 180 ° C. was 26 Pa.s. s containing hot melt composition 1 (see table), each having an average thickness of about 100 μ 18 × 18 yarns / cm
^It was applied to a PET cloth containing ² by the extrusion coating method.
Experiments were carried out using a L / D = 30 Brabender single screw-extruder with a 10 cm wide slit die and a die gap of approximately 1 mm. The hot extruded sheet (melting temperature in the die was 155 ° C) was immediately applied to a cloth and wound by a three roll "take up" device.

In this apparatus, the upper and lower rolls are movable and connected to a fixed roll in the middle via a spring, thereby compressing the sheet and the cloth to some extent.

The distance between the rolls was set to about 1.5 mm. The temperature of the first two rolls was 80 ° C, while the temperature of the third roll was about 15 ° C. A sheet of about 1 mm was continuously applied to the cloth by this device.

The PET fabric threads were composed of short (cut) filaments to improve adhesion. The adhesion between the composition and the PET fabric was measured by a T-peel test according to ASTM D 1876. Cohesive failure was observed for all measured samples, which means that the adhesion is at least 2.5 N / mm.

Examples 2-6 Hot melt compositions 2-6 described in Table 1 were prepared with varying amounts of block copolymer components. Example 1
The same PET cloth was applied in the same manner as described in.

Adhesion between all compositions and the fabric was similarly measured and found to be at least 2.5 N / mm.

[0059]

[Table 1]

All compositions in Table 1 had 3 parts by weight of KE
Includes MAMIDE E, 1 part by weight Tio ₂ and 1 part by weight IRGANOX 1010.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Teunis Fullerfurant Belgium, Louvain-la-Neuve, Bé-1348 Ottinje, Abunyu Jean Monet 1

Claims (17)

[Claims] 1. A method comprising: (a) at least two terminal poly (vinylaromatic) blocks and at least one internal poly (conjugated diene) block, wherein the poly (conjugated diene) blocks have an initial ethylenic unsaturation of at least 80. % Of the block copolymers are selectively hydrogenated and optionally modified by grafting polar moieties,
A hot melt composition suitable for the manufacture of conveyor belts comprising (b) a non-aromatic plasticizing oil and (c) an end block compatible resin. 2. A selectively hydrogenated block copolymer comprising (a) a substantially pure poly (styrene) block and a substantially pure poly (butadiene) or poly (isoprene) block. The hot melt composition according to claim 1, which is used as a component. 3. A carboxylic acid or a derivative thereof, an epoxy compound, a selectively hydrogenated block copolymer,
A copolymer modified by grafting a polar substance such as a silane compound, an amine or an amide is (a).
Use as an ingredient, 1 and 2 characterized in that
The hot melt composition according to. 4. The hot melt composition according to claim 3, wherein the poly (conjugated diene) block is grafted with maleic anhydride or an acrylic ester. 5. A non-modified selectively hydrogenated block copolymer and a modified selectively hydrogen in a weight ratio in the range of 95/5 to 40/60, preferably 80/20 to 50/50. The hot melt composition according to claim 1, wherein a mixture with the block copolymer which has been polymerized is used as the component (a). 6. A hot melt composition according to claim 1, characterized in that a petroleum-derived oil which is completely non-aromatic is used as component (b). 7. The hot melt composition according to claim 1, wherein a polyolefin having a molecular weight in the range of 500 to 6,000 is used as the component (b). 8. The hot melt composition according to claim 7, wherein the polyolefin is used in an amount of 100 to 200 parts by weight per 100 parts by weight of the block copolymer. 9. 5 per 100 parts by weight of the block copolymer
0 to 150 parts by weight, preferably 100 block copolymer
The hot melt composition according to claim 1, wherein 75 to 125 parts by weight of the end block modified resin is used per part by weight. 10. In addition to the three main components, one or more auxiliaries such as stabilizers, fillers, colorants, slip agents and additional thermoplastic polymers are included. The hot melt composition according to. 11. The hot melt composition according to claim 10, wherein LLDPE is included as an additional polymer. 12. 20 to 300 μ, preferably 100
A cloth having yarns having a thickness of μ to 300 μ in both directions of 5 to 25 yarns / cm, preferably 10 to 20 yarns / cm, and more preferably 15 to 18 yarns / cm.
A conveyor belt obtained by applying the hot melt composition according to 1. 13. The coating density of the hot melt composition is 0.5 to 3 g / cm ² , preferably 1 to ² g / cm ^2.
The conveyor belt according to claim 12, characterized in that 14. Conveyor belt according to claim 12, characterized in that a PET fabric with long filaments and / or pretreated with resorcinol-formaldehyde latex is used as starting fabric. 15. The conveyor belt of claim 14, wherein the PET fabric has cut filaments that impart a textured surface to the fabric. 16. 0.5-5 mm, preferably 1-3 m
16. The method of manufacturing a conveyor belt of claims 12-15, comprising applying the hot melt composition to the fabric to form a one-sided coating layer having a thickness in the range of m. 17. The method of claim 16 wherein the application of the hot melt composition is performed by an extrusion coating process using a three roll take-up device to compress the sheet and fabric. .