Thermoplastics articles having a surface fused to cloth

Thermoplastics articles having surfaces laminated to cloth are made without distortion of the cloth by using a melded cloth, that is to say a cloth composed of contiguous conjugate fibres fused together at points where they touch one another. The articles can be made by moulding thermoplastics materials onto melded cloth inserted into a mould.

This invention relates to thermoplastics articles having a surface keyed to 
cloth. The articles may comprise moulded thermoplastics material in a 
solid state or they may comprise the so-called moulded structural foams in 
which a foamed core is covered with a solid thermoplastics skin. 
It is often impossible to make a thermoplastics article by a moulding 
process without producing swirl marks or other disfigurations on the 
surface of the resulting article. This is especially true of processes 
which produce structural foams. For some articles such as furniture 
components or components used as motor vehicle trims it is useful to stick 
a cloth covering onto the surface of the article to hide the 
disfigurations and at the same time produce an upholstered appearance. 
Attempts to stick cloth on to an article during the moulding process have 
been unsatisfactory because the thermoplastics material is usually 
subjected to pressures in excess of 15 Kg/cm.sup.2 which causes the flow 
of the heat-softened thermoplastic which occurs during moulding to distort 
the cloth and/or penetrate through the cloth destroying its upholstered 
feel and creating ugly blemishes. 
This invention provides a thermoplastics article having a surface region 
keyed into a piece of cloth which is a non-woven cloth having a thickness 
of at least 0.6 mms and preferably 0.8 to 4 mm and a weight of 50 to 250 
g/m.sup.2, preferably 80 to 150 g/m.sup.2. Preferably the cloth comprises 
at least 25% by volume of contiguous conjugate fibres at least some of 
which are fused together at at least some of the points where they touch 
one another, each conjugate fibre comprising two mutually adhering 
fibre-forming components one of these which forms at least part of the 
surface of the fibre can be rendered fusible by a treatment which does not 
significantly affect the other component so as to enable contiguous fibres 
to be fused together. Such cloths composed of fused contiguous fibres are 
often referred to as "melded" cloths. Melded cloths are preferred because 
they are particularly resistant to removal from the thermoplastics article 
by pulling by hand. 
Examples of melded cloths which may be used in the performance of this 
invention are described in United Kingdom patent specification No. 
1,245,088. The melded cloths may additionally comprise fibres other than 
conjugate fibres such as cotton, wool, polyethylene terephthalate, nylon 
or polypropylene fibres. The term "fibre" is used to include not only 
staple fibres but also filaments and yarns in general. Preferred conjugate 
fibres include fibres comprising a core of nylon 66 or polyethylene 
terephthalate in contact with or preferably sheathed in nylon 6 or a nylon 
6/nylon 66 copolymer or a polyethylene terephthalate/isophthalic 
copolymer. The terephthalate/isoterephthalate copolymer preferably 
comprises from 5 to 25% by weight of copolymerised isophthalic acid. 
Alternatively the conjugate fibre may comprise a core of polypropylene in 
contact with nylon 6 or polyethylene especially if the thermoplastics 
article comprises plasticised polyvinyl chloride. 
This invention also includes a method for making a thermoplastics article 
having a surface region keyed into a piece of cloth wherein the non-woven 
cloth is positioned against an article-defining surface of a mould, a 
flowable thermoplastics material is introduced into the mould and is 
contacted with the cloth while under pressure and at a temperature above 
the softening point of the thermoplastics material. At least one component 
of the cloth should be capable of remaining form-stable during the 
process. The method is preferably performed using an injection moulding 
technique particularly if it is desired to produce a structural foam. In 
an injection moulding process, the mould is filled with molten 
thermoplastics material under pressure. 
The method may also be performed using a blow moulding technique in which 
case thermoplastics material in a heat-softened state is caused to flow 
into contact with the non-woven cloth under the influence of the pneumatic 
pressure used to expand the parison. 
If thermoplastics such as polyethylene or polyvinyl chloride are to be 
used, the method may be performed using a rotational moulding technique. 
For example a polyethylene powder or a polyvinyl chloride plastisol could 
be introduced into a rotatable mould and heated while the mould is 
rotated. Therefore this invention provides a method for making a 
thermoplastics article wherein the non-woven cloth is positioned against 
an article-defining surface of a rotatable mould, a powder or plastisol of 
thermoplastics material is introduced into the mould and then the mould is 
heated and rotated to rotationally mould the thermoplastics material. 
Alternatively thermoplastics may be keyed to the melded cloth by 
calendering (e.g. plasticised polyvinyl chloride) or extrusion coating 
(e.g. polyethylene or polypropylene) onto the melded cloth. In particular 
this invention provides a method for making a thermoplastics article 
wherein thermoplastics material is extrusion coated onto the non-woven 
cloth and the coated cloth is passed through nip-rollers while the 
thermoplastics material is still in a flowable condition. 
The thermoplastics materials used in the performance of this invention are 
preferably crystalline polyolefins, particularly polymers or copolymers of 
propylene and ethylene and including copolymers of ethylene with up to 40% 
by weight of unsaturated esters of carboxylic acids such as vinyl acetate 
or alkyl acrylates and methacrylates.

The invention is illustrated by the following Examples. The melt flow index 
quoted in the Examples was measured according to British Standard 2782: 
Part 1/105C/1970 using a 2.16 kg load but carried out using a temperature 
of 230.degree. C. instead of 190.degree. C. 
EXAMPLE 1 
A melded cloth was made by passing a felt of contiguous conjugate fibres 
(each fibre consisting of a nylon 66 core enclosed in a nylon 6 sheath) 
through a pair of calender rollers. The upper roller was provided with 
heated teeth which pressed down on the felt causing the outer sheaths of 
contiguous compressed fibres to fuse together in the region of the 
compression and thus form a melded cloth. The cloth had a thickness of 1mm 
and a weight of 120 g/m.sup.2 and was of the type normally used as curtain 
material. A piece of the melded cloth was then keyed onto a moulded plaque 
by the following process. 
A plaque-defining injection mould was opened and the piece of melded cloth 
was laid over one of the plaque-defining surfaces of the mould and held in 
place by adhesive tape. The plaque defined by the mould was 6 inches by 6 
inches square and 0.25 inches thick (i.e. 15.3.times.15.3.times. 0.63 cm) 
and the piece of cloth was also 6 inches by 6 inches square. The mould was 
closed and filled with molten polypropylene at a temperature of 
240.degree. C. and having a melt flow index of 4.0 g/10 mins. The molten 
polypropylene was injected into the mould under a positive injection 
pressure of 700 Kg/cm.sup.2. The polypropylene was allowed to cool for 
21/2 minutes in the mould and then the mould was opened and the plaque 
removed. 
On inspection of the cooled plaque it appeared that the molten 
polypropylene had been forced into intimate contact with a surface region 
of the melded cloth so that on solidification of the polypropylene a 
plaque was formed having a surface region which conformed closely to the 
surface region of the cloth thus producing a keying effect which held the 
cloth firmly onto the plaque. Attempts to pull the cloth from the plaque 
by hand were unsuccessful. Despite the keying effect of the polypropylene 
the melded cloth retained its cloth-like feel. No evidence of distortion 
could be seen in the cloth and no significant relaxation of the fibres 
appeared to have occurred. 
COMATIVE EXAMPLES A TO F 
The procedure of Example 1 was repeated but instead of melded cloth, the 
following non-melded cloths were used: 
A. Closely woven acrylic curtain cloth: It was discovered that when this 
cloth was used, molten polypropylene readily penetrated the cloth and 
covered parts of the visible surface of the cloth (i.e. that surface which 
is not keyed to the thermoplastics article and which is visible when the 
article is in use). Even where the visible surface of the cloth had not 
been covered, sufficient penetration of the cloth by polypropylene had 
occurred to cause the cloth to lose its textile feel. The cloth had been 
badly distorted by the flow of the molten polypropylene. 
B. Closely woven nylon upholstery cloth provided with a woven backing 
composed of nylon and cotton fibres: It was discovered that penetration of 
this cloth by the polypropylene was not excessive and in particular it did 
not lose its textile feel. However the cloth could be easily pulled from 
the plaque by hand. 
C. Upholstery cloth made from polypropylene fibres: It was discovered that 
the polypropylene fibres partially fused with the molten polypropylene and 
although the pattern remained intact the textile feel was lost. 
D. Closely woven linen curtain cloth: It was discovered that the molten 
polypropylene had penetrated the cloth as in comparative Example A but in 
this case the cloth was even more badly distorted. 
E. Closely woven cotton curtain material: It was discovered that the molten 
polypropylene would not flow easily over the surface of the cotton cloth 
and as a result it was impossible to fill the mould using the conventional 
pressures employed in Example 1. The cotton cloth could also be pulled 
from the plaque by hand. 
F. Closely woven woolen upholstery material: It was discovered that the 
molten polypropylene would not flow easily over the surface of the woolen 
cloth and as in comparative Example F it was impossible to fill the mould 
using the pressure used in Example 1. Increasing the pressure in order to 
fill the mould caused excessive penetration of the woolen cloth and 
destroyed its textile feel. 
EXAMPLE 2 
A length of melded cloth of the kind used in Example 1 was extrusion coated 
with a layer of polypropylene using a standard extrusion coating 
technique. The polypropylene had a melt flow index of 5 and contained 2.5% 
by weight of carbon black. The coated cloth was passed through nip rollers 
while the polypropylene was still in a flowable condition. On cooling it 
was discovered that the polypropylene had keyed firmly to the melded 
cloth. 
Preferably the thermoplastics used in the performance of this invention 
should be moulded at from 200.degree. to 300.degree. C. and at pressures 
of 20 to 1,000 Kg/cm.sup.2. Injection moulding is usually carried out at 
200.degree. to 250.degree. C. using pressures of 500 to 1,000 Kg/cm.sup.2. 
Preferably the polypropylene used in the performance of this invention 
should have a melt flow index of from 0.1 to 30 g/10 minutes and in 
particular the melt flow index usually lies in the range 1 to 10 g/10 
minutes. 
In a modification of this invention particularly desirable when the 
thermoplastics articles are articles of furniture, melded cloth is used 
which contains a flame retardant additive or additive combination or which 
has been subjected to a flame retardant treatment. 
An embodiment of the invention will now be described with reference to the 
drawing which shows a vertical section through a chair component made 
according to this invention. The FIGURE shows a thermoplastics chair 
component 1 fused to a melded cloth covering 2.