WO1999036263A1

WO1999036263A1 - Roughed plastic films having increased tensile strength

Info

Publication number: WO1999036263A1
Application number: PCT/HU1998/000026
Authority: WO
Inventors: József Sen. MANDZSU; József MANDZSU, Jr.; Zoltán MANDZSU
Original assignee: Mandzsu Jozsef Sen; Mandzsu Jozsef Jr; Mandzsu Zoltan
Priority date: 1998-01-20
Filing date: 1998-03-18
Publication date: 1999-07-22
Also published as: AU6741398A

Abstract

The invention relates to roughed plastic films having increased tensile strength. The essence of the invention is that it has, at least on its surface to be made antislip, on the entire surface or on specified areas of that, as antislip plastic layer comprising protrusions welded into and at least partially sticking out of the surface, consisting of the substance of the antislip layer and/or other particles capable of welding with the material of the antislip layer, and, directly or indirectly fixed to the other surface of the antislip plastic layer, a strength-increasing plastic layer comprising at least two oriented components fixed to each other to form one unit and having typical orientation directions staying within the layer but otherwise different from (preferably perpendicular to) each other. The invention involves the hot resistant, roughed plastic films having increased tensile strength as well.

Description

Roughed plastic films having increased tensile strength

Technical Field

The invention relates to roughed plastic films having increased tensile

strength.

10 It is known that the use of thermoplastic films in the technical life,

shipment, trade and in the different fields of articles in daily use as well as

for a number of different utilization purposes are wide-spread.

Depending on the field of employment, in general the plastic films

must have two essentially important qualities; namely they must have an ap-

i ? propriate strength (tensile strenth) and must be antislip.

The strength may be enhanced by choosing a suitable substance, in¬

creasing the thickness or creating orientation in the structure of the plastic

material.

Background Art

0 In the plastics industry the term 'orientation' means how the molecule

chains are ordered in the plastic films. Orientation in the demanded direction

in the film may be carried out by expanding the film in the given direction

during the manufacturing procedure. The tensile strength of the film against

the tensile stress acting in the direction of the orientation may be significantly

5 increased by a strong orientation, however simultaneously the tensile

strength will decrease in the direction perpendicular to that. Thus a film, strongly oriented in one direction, is distinctly able to withstand stresses acting in the direction of the orientation, but its tensile strength perpendicularly

to that direction is weak.

In practice among others plastic layers having high tensile strength

both lengthwise and crosswise are produced in a way that strongly oriented

components having different (preferably perpendiculary to each other) orien¬

tation directions are fixed together in the way of forming one unit. That may be carried out for example by fixing the suitably oriented plain plastic films to

each other and fitted to each other, i.e. by lamination or by forming a woven, knitted or non-woven structure from drawn plastic (for example polypropyl¬

ene) fibres.

According to the present state of the art the antislip characteristic was

achieved in accordance with the most obvious procedure in a way that sur¬

faces lying on each other were coated with adhesives. But this solution has

raised the problems of choosing the adhesive and the quality of the adhe¬

sive, and in fact, the efficiency of the solution was made worse by a dusty

environment. When an adhesive of an excellent quality was used, it has

been difficult to disengage the surfaces and many times it might lead to

damaging of the surfaces. However using of an adhesive of a poor quality,

due to the insufficient adhesion strength, the task could not be deemed to be solved either.

As an other type of solution it was tried to create antislip surfaces by

forming unevenness from the material of the film. According to a typical so¬

lution of that kind the film was embossed from the direction of the internal

side, so bumps were formed on the side where the slipping had to be pre- vented. It was also tried to create ribs longitudinally in the films' surface, but by this means the problem was solved in part only, because the slipping only

partly, in one direction could be prevented.

A solution was also elaborated where the unprocessed plastic gran-

ules were mixed with extraneous substances which could not be incorporated homogenously into the basic plastic and humps were formed. How¬

ever, in the course of that kind of method the extruder and the connected

passing cylinders were exposed to abrasion, so the tool was getting deterio¬

rated too early and besides it was inpossible to keep control over the dis- posal of humps as it would have been required.

A procedure was also applied, where humps were formed on both

sides of the film by mixing the raw material with some chemical additive. The

drawback of that procedure is its high cost, because the additive, having a

high price, was demanded in quite large quantities, and also that both sides

of the product were provided with humps, which limited the scope of utiliza¬

tion.

All of the aforementioned procedures are costly, uneconomical and

are not as efficient as it would be required. These methods were used be¬

cause until now there have been no adequate processes which would solve

the problem favourably.

Another solution of our own satisfied a still existing - essentially previ¬

ously not satisfied - demand, inasmuch as, by elimination of the aforemen¬

tioned problems, solved the given technical task. According to this solution

particles consisting of the substance of the film and/or other plastic material

being able to weld together with that, and having suitable size and/or de- manded abrasion resistance are brought to the surface to be roughed of semi-finished product having sufficient reserved heat content to maintain

condition appropriate for welding of the thermoplastic film surface to be

roughed or to one or both film-surfaces re-heated to such temperature and

are dispersed in suitable closeness and configuration and that condition of

the roughed surface is maintained until desired welding process is com¬

pleted.

From the point of view of creating antislip surfaces one of the most

effective solutions is the roughed plastic film. The antislip quality of the sur-

face may be improved with the increase of the number of the particles per

one surface unit.

The antislip characteristics and the large mechanical strength are contradictory requirements raised against a conventional roughed film be¬

cause of the following:

The number of particles per one surface unit of the roughed plastic

film is standing in inverse ratio to the degree of the orientation (expanding of

the film during the manufacturing procedure) (in case of a given arrange¬

ment the closeness of the particles will be reduced by increasing the orien¬

tation), however in order to reach the demanded mechanical strength of the

roughed film as much orientation would be needed as possible.

In addition, this solution has raised a further problem of choosing the

suitable raw material, because the tensile strength parameters of the raw

material that are the most suitable in the respects to the roughening proce¬

dure (e.g. producibility or availability in particle form, or welding capability

with the available particles and the characteristic how easy to induce and maintain the condition appropriate for welding, etc.) are far behind those of other possible raw materials which way otherwise come into question

According to the conventional methods known from the state of the art

it is difficult to realize the good antislip feature and high mechanical strength

of the roughed plastic film simultaneously. For example one possible way is greatly increasing the thickness of the film but this results in higher costs and

also may involve other application drawbacks.

Disclosure of Invention

Hence it follows that the object of the invention is to provide roughed

plastic film having increased tensile strength which is able to combine the large tensile strength coming from the strong orientation and, due to the

roughening, the antislip characteristics, and, in addition, whose way of preparation.

The invention is based on the recognition that if the plastic film has at

least on its surface to be made antislip, on the entire surface or on specified

areas of that, an antislip plastic layer comprising protrusions, welded into

and at least partially sticking out of the surface, consisting of the substance

of the antislip layer and/or other particles capable of welding with the mate¬

rial of the antislip layer and a strength-increasing plastic layer, properly, di-

rectly or indirectly fixed to the other surface of the antislip plastic layer then it

can be reached that the film, due to its roughened surface, has in respect to

the demand of the antislip feature, optimum roughness and antislip charac¬

teristics and, simultaneously, due to the strenght-increasing layer, its

strenght most favourably satisfies the planned mechanical strength demand and in addition the entire thickness of the film layer and thereby the costs of

preparation connected with that could remain at a low level.

The raw material of the roughed film and the protrusions welded into

that, the thickness of the film, the size, closeness and distribution of the pro-

trusions can be the most preferable values in respect to the required antislip

quality.

Thus the essence of theroughed plastic film having increased tensile

strength in accordance with the present invention is that it has, at least on its

surface to be made antislip, on the entire surface or on specified areas of

that, as antislip plastic layer comprising protrusions welded into and at least

partially sticking out of the surface, consisting of the substance of the antislip

layer and/or other particles capable of welding with the material of the an¬

tislip layer, and, directly or indirectly fixed to the other surface of the antislip

plastic layer, a strenght-increasing plastic layer comprising at least two ori-

ented components fixed to each other to form one unit and having typical

orientation directions staying within the layer but otherwise different from

(preferably perpendicular to) each other.

Thus, in order to obtain the appropriate tensile strength, the thermo¬

plastic strength-increasing layer comprises at least two strongly oriented

components fixed to each other in the manner of forming one unit, having

orientation directions staying within the layer, but within that different from,

preferably perpendicular to each other. Accordingly for example the

strength-increasing layer may consist of plane films suitably oriented and

fixed to each other (e.g. laminated multilayer system) or a structure built-up from drawn plastic (e.g. polypropylene) fibres such as woven fabric, net, knitted cloth and the like.

Between the antislip layer and the strength-increasing layer there can

be one or more different (e.g. binding) layers as well. In respect to the utili-

zation there is an important requirement, namely that the shearing resis¬

tance of the mechanical joint formed between the antislip layer and the strength-increasing layer should exceed the planned greatest value of the

average friction stress acting on the antislip layer caused by the external

factors in the course of application. This is necessary to avoid the disen-

gagement of the individual layer components even under the greatest stress

in the course of the utilization.

The strength of the roughed plastic films having increased tensile strength is determined by the strength of the strength-increasing layer and

the antislip characteristic of that depends on the antislip characteristic of the

antislip layer.

Best Mode for Carrying Out the Invention

For economic reasons, depending on the planned utilization stress, at

certain applications the extent of the strength-increasing layer may be

smaller than the size of the surface of the antislip layer, i.e. the antislip layer

has a strenght-increasing layer fixed to it in a certain part of its surface only

but such a construction, where, fixed onto the continuous strenght-increasing

layer, there is a non-continuous antislip layer or one that does not entirely

cover it, is also possible. The fixation of the aforementioned layers may be carried out for ex¬

ample by sticking, sewing, welding or the strenght-increasing layer can be

coated with the antislip layer in its moulded state.

The strength-increasing layer can be for example hose, sack or plain

fabric preferably having a substance of polypropylene.

The average height of the surface protrusions of the antislip layer is

preferably more than 100 microns, more preferably is more than 100 mi¬

crons and less than 300 microns.

Antislip layers may be fixed onto both sides of the strength-increasing

layer.

The antislip layer may comprise non-roughed surface-parts as well.

On the other hand also in case of heat resistent packaging materials

slipping surfaces may create difficulties at a number of applications. For ex¬

ample the slipping of paper sacks containing cement powder in the course of

shipment causes damage in the load and additional costs of the interplant

transport.

Hence the object of the invention is also to provide a packaging mate¬

rial simultaneously having a roughed plastic layer and a heat resistent

strength-increasing layer, which combine the large mechanical strength,

coming from the characteristics of the heat resistant raw material and re¬

maining also at the planned highest application temperature, with the antislip

features created by roughening.

We have found that drawbacks coming from the state of the prior art

may be eliminated by utilization of the roughed film because on the film side

towards the content to be packaged having a higher temperature the crite- rium of heat resistance, while on the external side antislip characteristic, has

to dominate

The essence of the packaging material of the invention having in¬

creased heat resistance is that it has at least on its side to be made antislip

5 on the entire surface or on specified areas of that a plastic layer comprising

protrusions consisting of the substance of the plastic layer and/or other par¬

ticles being able to weld together with the substance of the plastic layer,

which are welded into the surface and at least partly standing out of that and

to its other surface in a suitable manner, directly or indirectly, a strength-

lo increasing layer made of a non-thermoplastic substance having a tensile

strength at 80°C at least eigthy percent of its tensile strength shown at 25°C,

is fixed

In accordance with a preferable embodiment of the invention the heat

resistant strength-increasing layer is paper

i s For economic reasons, depending on the planned utilization stress, at

certain applications the extent of the heat resistant strength-increasing layer

may be smaller than the size of the roughed surface, i e the roughed plastic

layer has a heat resistant strength-increasing layer fixed to it in certain part

of its surface only However, such a construction, where, fixed onto the con-

0 tinuous strength-increasing layer, there is a non-continuous roughed plastic

layer or one that does not entirely cover it, is also possible

In case of further preferable embodiments the heat resistant strength-

increasing layer is linen, fabric, a fabic of glass fibres non-thermoplastic

substance The individual layers of the packaging material in accordance with the

present invention may be fixed by sticking, sewing or the heat resistant strength-increasing layer can be coated with the roughed layer in its

moulded state.

The packaging material in accordance with the present invention -

among others - can be formed as a horse, a bag or a sack.

At a preferable embodiment the average height of the surface protrusions of the roughed layer is more than 100 microns, more preferably is more than 100 microns and less than 300 microns.

Claims

- I I -

What we claim is

1 Roughed plastic film having increased tensile strength characterized in

that it has, at least on its surface to be made antislip, on the entire sur-

face or on specified areas of that, as antislip plastic layer comprising protrusions welded into and at least partially sticking out of the surface,

consisting of the substance of the antislip layer and/or other particles

capable of welding with the material of the antislip layer, and, directly or

indirectly fixed to the other surface of the antislip plastic layer, a strenght-increasing plastic layer comprising at least two oriented com¬

ponents fixed to each other to form one unit and having typical orienta¬

tion directions staying within the layer but otherwise different from

(preferably perpendicular to) each other

Film as claimed in claim 1 wherein the strength-increasing plastic layer

is a fabric or a net

3 Film as claimed in claim 1 wherein the strength-increasing plastic layer

is a multilayer laminated film

Film as claimed in any of claims 1 to 3 wherein its strength-increasing

layer is fixed to the antislip layer with adhesive

Film as claimed in any of claims 1 to 3 wherein its strength-increasing

layer is sawn to the antislip layer

Film as claimed in any of claims 1 to 3 wherein its strength-increasing

layer is welded to the antislip layer

Film as claimed in any of claims 1 to 3 wherein the the antislip layer is

fixed to the strength-increasing layer by coating in a moulded condition

8. Film as claimed in any of claims 1 to 7 wherein the antislip layer does

not entirely cover the strength-increasing layer.

9. Film as claimed in any of claims 1 to 7 wherein the strength-increasing

layer does not entirely cover the antislip layer.

10. Film as claimed in any of claims 1 to 9 wherein its strength-increasing

layer is a hose or a sack.

1 1. Film as claimed in any of claims 1 , 2 or 4 to 10 wherein its strength-

increasing layer is a polypropylene fabric.

12. Film as claimed in any of claims 1 , 2 or 4 to 11 wherein its strength-

increasing layer is a polypropylene plane fabric.

13. Film as claimed in any of claims 1 , 2 or 4 to 11 wherein its strength-

increasing layer is a circularly woven polypropylene fabric.

14. Film as claimed in any of claims 1 to 13 wherein the average height of

the surface protrusions of the antislip layer is more than 100 microns.

15. Film as claimed in any of claims 1 to 13 wherein the average height of

the surface protrusions of the antislip layer is more than 100 microns

and less than 300 microns.

16. Film as claimed in any of claims 1 to 15 wherein antislip layers are fixed

on both sides of the strength-increasing layer.

17. Film as claimed in any of claims 1 to 16 wherein the antislip layer is

comprising non-roughed surface-parts as well.

18. Packaging material having heat resistent strength-increasing layer and

roughed plastic layer characterized in that it has at least on its side to

be made antislip on the entire surface or on specified areas of that a

plastic layer comprising protrusions consisting of the substance of the plastic layer and/or other particles being able to weld together with the

substance of the plastic layer, which are welded into the surface and at

least partly standing out of that and to its other surface in a suitable

manner, directly or indirectly, a strength-increasing layer made of a

non-thermoplastic substance having a tensile strength at 80 °C at least

eigthy percent of its tensile strength shown at 25 °C, is fixed.

19. Packaging material as claimed in claim 18 wherein the heat resistant strength-increasing layer is paper.

20. Packaging material as claimed in claim 18 wherein the heat resistant

strength-increasing layer is linen, cloth, other fabric, a fabric of glass fi¬

bres or non-thermoplastic substance.

21. Packaging material as claimed in any of claims 18 to 20 wherein the heat resistant strength-increasing layer is fixed to the roughed plastic layer with adhesive.

22. Packaging material as claimed in any of claims 18 to 20 wherein the

heat resistant strength-increasing layer is sawn to the roughed plastic

layer.

23. Packaging material as claimed in any of claims 18 to 20 wherein the

roughed plastic layer is fixed to the heat resistant strength-increasing

layer by coating in a moulded condition.

24. Packaging material as claimed in any of claims 18 to 23 wherein the

roughed plastic layer does not entirely cover the heat resistant strength-

increasing layer.

25. Packaging material as claimed in any of claims 18 to 23 wherein the heat resistant strength-increasing layer does not entirely cover the roughed plastic layer.

26. Packaging material as claimed in any of claims 18 to 25 wherein the

packaging material is formed as a hose, a bag or a sack.

27. Packaging material as claimed in any of claims 18 to 26 wherein the average height of the surface protrusions of the roughed layer is more

than 100 microns.

28. Packaging material as claimed in any of claims 18 to 27 wherein the

average height of the surface protrusions of the roughed layer is more

than 100 microns and less than 300 microns.

29. Packaging material as claimed in any of claims 18 to 28 wherein the roughed layer is comprising non-roughed surface-parts as well.