GB2519509A

GB2519509A - Insulator pads

Info

Publication number: GB2519509A
Application number: GB1316788.7A
Authority: GB
Inventors: Timothy John Wilson; Stephen Andrew Midgley
Original assignee: John Cotton Group Ltd
Current assignee: John Cotton Group Ltd
Priority date: 2013-09-20
Filing date: 2013-09-20
Publication date: 2015-04-29
Anticipated expiration: 2033-09-20
Also published as: GB201316788D0; GB2519509B

Abstract

An insulator pad for use in spring based upholstery comprises an embossed thermoplastic bound fibre based nonwoven material having regions of a first density isolated by interconnected regions of a second density. The second density may be higher or lower than the first density. The pad preferably comprises less than 18% by weight thermoplastic binding fibres which provide the thermoplastic bonding. The pad may be produced by subjecting a batt comprising thermoplastic binding fibres to a temperature sufficient to melt the thermoplastic fibres and then subjecting the batt to variable compression to form an embossed pad with the regions of relatively high and low density. The batt may be compressed using an embossing roller with projecting elements 20. The pad is preferably made from recycled fibres and the bonding fibres may be polyolefin (such as recycled polypropylene) and/or polyester. The pad material preferably has a mean weight of 300 to 2500 g/m2, a mean thickness of 3 to 20mm and/or mean density of 50 to 300 kg/m3.

Description

INSULATOR PADS

FIELD OF INVENTION

[0001] The present invention is concerned with insulator pads used in upholstered products and in particular with high density insulator pads, their method of manufacture and articles incorporating such pads.

BACKGROUND ART

[0002] Upholstered structures occur in a wide range of products including beds, mattresses, general furniture including articles such as sofas, armchairs and seats and also in seating etc within the transport industry. One particular form of upholstered structure is based on the use of spring units that provide mechanical support and recovery from compression during use of the product incorporating the structure. The spring units comprise multiple metal coils above which are placed one or more layers of material typically textile/nonwoven or foam layers. One challenge with such structures is to reduce the likelihood of the metal springs penetrating low density fabric or foam layers that may be in contact with or proximate to these springs and causing damage to them. The conventional solution to this problem is to place an additional, relatively high density fabric layer known as an "insulator pad" between the spring and the fabric layers often immediately on top of the spring unit and directly beneath the textile/nonwoven or foam layers.

I

[0003] One commonly manufactrued form of insulator pad is based on the use of nonwoven materials. These nonwoven insulator pads typically comprise a blend of recycled and/or virgin textile fibres of mixed polymer composition. A key component is the use of thermoplastic binder fibres, such as for example polypropylene fibres. These thermoplastic binder fibres are used to develop adequate tensile and burst strength in the fabricated insulator pad.

These is achieved through heating and thermal bonding. During heating thermal bonding occurs as the thermoplastic binder fibres on heating exhibit full or partial melting of the fibre surfaces. Meltflow from these fibres serves to create physical bonds between proximal fibres, thereby increasing the strength of the fabricated inuslator pad once the molten polymer has cooled.

[0004] Thermal bonding manufacturing process typically involves a two-stage continuous process. In the first stage a drylaid web or batt (a fibrous assembly held together by friction) comprising the blended fibres with the thermoplastic binder fibres is first heated under low compression. Typically this is achieved by convection using an oven. This process is conventionally known as through-air bonding. After heating in the oven, the through-air bonded material is then processed in a second stage. The through-air bonded web/matt emerging from the oven is compressed by means of a suitable unheated compression device and this is typicall a pair of smooth calender rollers. The use of smooth compression surfaces ensures complete area bonding wherein the entire area of the formed insulator pad has been compressed and the fibres are brought into intimate contact throughout the volume of the pad. This serves to uniformly increase the pad's volumetric density thereby producing a product with good resistance to spring penetration.

[0005] In practice it has been found that insulator pads manufactured from blends of recycled and/or virgin textile fibres with use of a thermoplastic binder fibre require the thermoplastic binder fibre content to be »=1 8% by weight of the pad. Levels of less than 1 8% by weight have resulted in insulator pads of lower strength that are susceptable to significant spring penetration. Under normal circumstances reducing the proportion by weight of the thermoplastic binder fibre is expected to compromise the strength of the insulator pad because of the reduced degree of thermal bonding that would be obtained.

[0006] However, in practice the incorporation of thermoplastic binder fibre at proportions of »=1 8% by weight in the insulator pad has certain disadvantages.

I

[0007] The thermal bonding thermoplastic binder fibre at these levels results in insulator pads that are relatively rigid and stiff; this renders it difficult to produce inuslator pads that conform to the sprung unit during assembly of upholstered products. Also, the thermoplastic binder fibre is typically composed S of a polymeric material that is derived from a petrochemical source, e.g. a polyolefin such as polypropylene or polyethylene. A reduction in the content of this component can be advantageous in terms of environmental sustainability, since the other components of the insulator pads are typically textile recyclate.

[0008] Thus, there is a need for new insulator pads and methods of their manufacture that eleviate one or more of the indicated problems associated with conventional insualtor pads. The purpose of the present invention is to address one or more of these needs.

DISCLOSURE OF THE INVENTION

[0009] It has been unexpectedly found that by using a specific process in the manufacture of insulator pads it is possible to produce insulator pads with improved properties at any given content of thermoplastic binder fibre compared to those manuactured using a conventional process. It has also been found, using this process that insulator pads may be produced with less than conventional levels of thermoplastic binder fibre but with equivalent or better properties than those achieved with conventional or higher levels of thermoplastic binder fibre manufactured using conventional processes.

Furthermore it has been found that the binder fibre may comprise mechanically recycled fibre. Mechanically recycled fibre in this context means fibres that have been recovered directly from other textile materials, without re-extrusion of the polymer. Thus, the insulator pad may be and preferably is produced entirely from recycled fibre content that has been obtained by mechanical disintegration of post-industrial or post-consumer waste via suitable recycling processes such as pulling or garneting processes.

[0010] Counterintuitively, this is accomplished by providing pad form materials wherein the total area of the pad material that is compressed during calendering after the thermal bonding step is reduced. When substantially reducing the extent to which the pad materials is compressed a reduction rather than an increase in fabric strength might normally be expected but the reverse has been observed.

[0011] Thus the present invention provides in a first aspect a pad form material comprising thermoplastic bound fibre based material, the material pad having embossed interconnected regions of high density thermoplastic bound fibre based material defining isolated regions of low density thermoplastic bound fibre based material. The material pad may have a mean weight of 300 -2500 g/m2, preferably 600 -2000 g/m2, a mean thickness of 3 to 20 mm, preferably 5 -15 mm and a mean density of 50 to 300 kg/m3, preferably 75 -250 kg/m3.

[0012] In a second aspect the present invention provides a pad form material comprising thermoplastic bound fibre based material, the material pad having embossed regions of high density thermoplastic bound fibre based material isolated within interconnected regions of low density thermoplastic bound fibre based material.

[0013] In both aspects of the present invention a region of high density material preferably has a mean density of greater than 150 kg/rn3, more preferably greater than 200 kg/rn3, more preferably 230 kg/rn3 or greater, preferably from 230 to 300 kg/m3 and most preferably from 230 to 250 kg/m3.

The region of low density material preferably has a mean density of 150 kg/m3 or less, more preferably 100 kg/rn3 or less.

[0014] With reference to both the first and second aspects there is a continuum of material between the high and low density regions within the material pads. It is also envisaged that a single pad may comprise embossed regions according to both the first aspect and the second aspect.

[0015] In a further aspect the present invention provides a pad form material of selectively compressed material comprising thermoplastic bound fibre based material and having a tensile strength greater than that of a completely uniformly compressed pad form material of the same composition.

[0016] In a further aspect the present invention provides a pad form material of selectively compressed material comprising thermoplastic bound fibre based material and having a tensile strength equivalent to or greater than a completely uniformly compressed pad form material comprising higher levels of thermoplastic binder fibres.

[0017] In a further aspect the present invention provides a method of making a pad form material, which method comprises: a) forming a fibre based batt comprising thermoplastic binding fibres; b) heating the batt to a temperature at which the thermoplastic binding fibres melt to form a thermoplastically bonded batt; c) introducing the thermoplastically bonded batt to a means for variable compression of the bonded batt and d) passing the thermoplastically bonded batt through the variable compression means to compress the batt to form an embossed pad form material having regions of high and low density material.

I

[0018] In a preferred method the fibre based batt of step (a) comprises post-industrial or post-consumer fibre recyclate, or a mixture thereof. Thus the batt may comprise a mixture of base fibre and thermoplastic binding fibre, both of which are provided from post-industrial or post-consumer fibre recyclate, or mixtures thereof. The batt may comprise base fibre from post-industrial or post-consumer fibre recyclate, or mixtures thereof in combination with fresh thermoplastic binding fibre or may comprise fresh base fibre with thermoplastic binding fibre from post-industrial or post-consumer fibre recyclate, or mixtures thereof. In a most preferred method the fibre based batt of step (a) is exclusively made up of post-iridusirial or posi-consumer fibre recyclale, or a mixthre thereof.

[0019] The variable compression produces regions of high and low density material in the final pad form material. The compression is selective according to a predetermined pattern of regions of high and low density. In one method the variable compression means comprises a pair of calender rollers defining a nip through which the thermoplastically bonded batt is passed, wherein at least one of the calender rollers has an embossed surface. In an alternative method the variable compression means comprises one or more mesh plates that may be used to compress the batt with or without passage through a calender roller nip. It is preferred that the variable compression stage is undertaken withoul heating. The variable compression means is such Iha regions of low density may be the result of that region having received no compressive forces during compression of the batt. However, it is preferred that after compression of the batt all regions (low and high density) have been formed under some level of compressive force.

[0020] In a further aspect the present invention provides an apparatus for manufactuhng a pad form matehal, the apparatus comphsng: means for formLng a fibre based batt compdsng thermoplastic binding fibres; means for heatThg the fibre based batt to a temperature above the meffing point of the thermoplastic binding fibres; means for transporting the thermoplastically bonded batt to a batt compression unit comprising means for variable compression of the ball, preferably al leasi Iwo opposing preferably unheated rollers defining a nip and wherein at least one of the rollers comprises an embossed surface, and means for passing the thermoplastically bonded batt through the variable compressing means to variably compress and emboss the batt and means for removal of the compressed batt. In an alternative the apparatus may comprise one or more mesh plates preferably unheated in place of the embossed calendar surface.

[0021] In a further aspect the present invention provides an upholstered product comprising one or more pad form materials according to the present invention.

[0022] The pad form materials of the present invention preferably comprise nonwoven materials. Preferably these nonwoven pad form materials comprise fibres. These fibres may be virgin textile fibres, recycled textile fibres, they may be a blend of fibres and may be a blend of recycled and virgin textile fibres. In addition to the bulk fibre component the pad form materials further comprise thermoplastic binder fibres. The bulk of the fibres present may be of a specific polymer compositions or may be of mixed polymer composition. A key component is the thermoplastic binder fibres. Suitable thermoplastic binder fibres are typically organic polymers that have the requiste properties to perform the function of a thermpolastic binder fibres. These thermpolastic binder fibres fibres must be easy to mix into and with the bulk fibre component of the pad form material. The thermoplastic binder fibres are preferably formed from an organic polymeric material having a melting point such that the polymeric material can flow at a temperature suitbale for the early stages of thermal bonding and not cause any damage to other components of the pad form material. Preferred organic polymers for use in the thermoplastic binder fibres are polyolefins and polyesters. The fibres comprising these polymers may be homofibres, that is fibres comprising a single type of polymer or may be bicomponent fibres, where there are two or more fibre types present. With the bicomponent fibres one or more of the polymers present may be a thermoplastic of the required properties for the thermoplastic binding fibres; this may be present in combination with a polymeric material that does not have these properties. As an example the bicomponent fibres may have a thermoplastic shell surrounding a core of different of limited thermoplastic properties, the shell providing the function of the thermoplastic binding fibres for use in the present invention and the core providing some additional mechanical support. A preferred thermoplastic binding fibre comprisies polypropylene. The thermoplastic binder fibres may be 100% mechanically recycled polypropylene (PP) obtained from post-industrial waste. Preferably the thermoplastic binding fibres has a fibre linear density of 2 -50 denier, preferably with a mean of 6 denier and preferably consisting of a mixture of fibre lengths ranging from 10 to 150 mm, more preferably 15 to 125mm and most preferably 20 mm to 100 mm.

[0023] During heating thermal bonding occurs as the thermoplastic binder fibres on heating exhibit full or partial melting of the fibre or fibre surfaces.

Meltf low from these fibres serves to create physical bonds between proximal fibres, thereby increasing the strength of the pad form material. The material of the thermpolastic binder fibres is flexible at and on solidifying when returing to ambient temperature once heat has been removed in the thermal bonding process. The thermoplastic binder fibres on melting impregnate the fibre network of the pad form material and on solidifying to a flexible state at ambient temperature help to develop adequate tensile and burst strength in the final fabricated pad form material. A preferred class of polymeric fibres are the polyolefin fibres that meet these criteria and a preferred polyolefin fibre is polypropylene fibre. It is preferred that the thermoplastic binder fibres consist wholly or in part of mechanically recovered fibre recyclate.

[0024] In the pad form materials of the present invention the thermoplastic binder fibres may be present at any suitable level within the pad form material and depending on the desired performance of the final pad form product. The percentage by weight may be varied depending on the extent of compression of the pad form material. The use of selective compression effectively opens up an area of compostional flexibility related to properties in the final pad form material that is not available with complete compression as used in the conventional processes. Thus if it is desired to achieve comparable properties to a completely uniformly compressed pad form material it is possible to achieve these properties using lower levels of thermoplastic binder fibres with selective compression. Also, if it is desired to achieve better mechanical properties in terms of tensile strength this may be achieved by using the same levels of thermoplastic binder fibres in combination with selective compression.

In one preferred arrangement the thermoplastic binder fibres are present at less than 1 8% by weight of the pad form material. In this arrangement it is typically desired to have comparable properties with those of a completely uniformly compressed pad form material having »=1 8% by weight of thermoplastic binder fibres. In alternative preferred arrangements the thermoplastic binder fibres may be present at equivalemt to or greater than 18% by weight of the pad form material. In this arrangement it is typically desired to have improved properties compared with those of a completely uniformly compressed pad form material having »=1 8% by weight of thermoplastic binder fibres. It should be understood that improved properties compared to any conventional pad form material may be achieved by a reduction in thermoplastic binder fibre levels in combination with selective compression or by maintaining the composition constant with the use of selective compression.

[0025] In preferred embodiments of all aspects of the present invention the thermoplastic binder fibres are present at less than 18% by weight of the pad form material and more preferably within the range of 5 up to 18% by weight, more preferably 10 up to 18% by weight and most prefearbly within the range of 10 to 15% by weight of pad form material.

[0026] The extent of compression of the pad form materials of the the present invention may be varied over a wide range. The total area of the pad form material that is selectively compressed may as much as 9O% (a reduction of 10% compared to the conventional materials) or as low as 20% (a reduction of 80% compared to the conventional materials). Prefearbly the total area of compresson of the pad form material is within the range of 20 to 90%, more preferably 30 to 80%, more preferably 30 to 70% and most preferaly 35 to 65%.

At area compression levels within the range of 35 to 65% it has been found that with some compositions the tensile strength of the pad form material can be increased by 100-300% and the burst strength by up to 60%.

[0027] With selective compression the overall density of the pad form material is reduced when compared to fully compressed pad form materials.

With selective compression some areas of the pad form material are of comparative or higher density than conventional pad form materials and some areas are of significantly lower density. The overall density will depend on the extent (area) of compression and the magnitude of compression.

[0028] It should be understood that selective compression includes a situation where a reduced area of the pad form material is compressed with the remaining area being exposed to no significant compression and also includes the situation where all areas of the pad form material are compressed to a degree but where selective areas are compressed to a higher degree than those that are partially compressed.

[0029] Thus in certain embodiments the final pad form material may comprise regions that are compressed and of realtively high density and regions that have no compression and have a density comparable to the pre-compressed pad form material after thermal bonding. In certain other embodiments the final pad form material may comprise regions that are compressed and of relatively high density and regions that have received lower levels of compression and therefore have a density that is higher than that of the pre-compressed pad form material after thermal bonding but less than the regions of high compression. It is envisaged that a selectively compressed pad form material according to the present invention may have a plurality of selectively compressed regions of differing density depending on the magnitude of compression. This variety of compression levels provides additional flexibility in formulation and manufacture of pad form materials with desired properties.

One important property that may be tailored by the use of selective compression and controlling of overall density is the stiffness of the pad form material. Use of selective compression in the pad form materials of the present invention leads to reduced stiffnes when compared to conventional pad form materials with compression of 100% of the pad area.

[0030] In the process of the present invention the first stage requires the formation of a fibre base batt comprising thermoplastic binding fibres. This batt may be formed using any conventional process known in the art for forming batt type structures. It is preferred that the batt is a drylaid batt. One preferred method for forming a drylaid batt comprising thermoplastic binding fibres is via airlaying. In this process typically the fibres are first mechanically separated and dispersed into a volume of air with a high dilution ratio to maintain their separation. This air-fibre dispersion is then transported to a permeable conveyor whereupon the fibres were deposited to enable batt formation.

[0031] The heating stage may be carried out in any conventional oven and preferably one that may accommodate a web of batting on a conveyor whose thickness is preferably greater than 20 mm. The oven will typically be operated at a temperature at or near to the melting point of the thermoplastic binding fibres and preferably high enough to ensure melt flow of at least the thermoplastic binding fibres in the bait. When the thermoplastic binding fibres comprise polypropylene this will typically be from 140 to 200°C and usually less than 190°C. Preferably before the batt is fully cooled it is subjected to compression by a separate device such as calender rollers that are preferably not heated.

[0032] The compression stage is a key stage in the process of the present invention. In a preferred embodiment this is accomplished by employing an embossed rather than smooth surface on at least one of a pair of opposed, unheated calender rollers operating at an applied pressure of between 5 bar (0.5 MPa) and 15 bar (1.5 MPa). The pre-heated batt passes into the nip of these unheated rollers and is selectively compressed by the embossed surface.

The resulting pad form material therefore consists of discrete regions of compressed and uncompressed regions rather than being uniformly compressed. In one modification the nip is such that the whole of the batt is compressed but that the regions of the batt exposed to the high points of the embossed surafce experience higher degrees of compression. When the batt passes through the nip of the rollers it may be at ambient temperature or may be at a higher temperature as it cools down from the heat bonding stage of the process. Preferrably the compression/embossing stage is performed with unheated roller surfaces.

[0033] The embossed surface can take the form of one or more engraved rollers, a metal plate or mesh, screen or drum. The manufacture of the surface can be accomplished by any method known in the art including engraving with an appropriate machine tool, pressing, moulding or etching.

[0034] The embossing pattern may be of any desired shape. In one embodiment it may be such that discrete points on the pad form material are compressed and surrounded by interconnected regions of uncompressed or partially compressed material. In another embodiment the embossing pattern may be such that an interconnecting pattern of compressed material is punctuated by islands of non-compressed material. A combination of these pattern types may be used.

[0035] In a preferred embodiment the pattern of embossing provides discrete regions of embossed material surrounded by interconnecting regions of low or no compression. It is preferred that area of each embossed element is carefully controlled. The area of an individual embossed element is preferably between 100 to 350 mm2, more preferably 150 to 300 mm2, more preferably to 260 mm2, and most preferably from 160 and 240 mm2. It has been found that by ensuing that the area of the individual embossed elements are within the narrower region of 160 and 240 mni2 that the highest levels of pad form tensile strength can be achieved.

[0036] Compression of the batt is accomplished by applying force such that pressure is generated. The roller pressure that is introduced is preferably from 5 to 15 bar.

[0037] In a further aspect of the present invention the batt may be compressed prior to entering the thermal bodning oven using the embossed surfaces. In this situation, compression by the embossed surfaces remains present on the bait during its passage through the bonding oven. This is conveniently accomplished by using a suitably patterned compression belt inside the oven or by placing an embossed screen upon the batt as it passes S throughtheoven.

[0038] Preferably, the shape of each engraved element is approximately rectangular with rounded edges. The long axes of each element are preferably oriented perpendicular to the direction of travel of the batt. The geometric arrangement of the engraved elements preferably consists of repeating unit cells of this form.

[0039] The pad form materials of the present invention may be used in a wide variety of upholstered structures including beds, mattresses, general furniture including articles such as sofas, armchairs and seats and also in seating etc within the transport industry. One particular preferred form is as unsulator pads for use in upholstered structures using spring units.

BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The present invention is exemplified and will be better understood upon reference to the following detailed description and examples when read in conjunction with the accompanying drawings in which: FIG. 1 is a schematic plan view of one embodiment of the present invention illustrating a preferred embossing arrangement; and FIG. 2 is a photograph of the surface of a preferred embossing roller for use in the process of the present invention.

[0041] With reference to Fig. 1 there is shown a preferred shape and arrangement of each engraved element (2) of an embossed pad form material (1). Each element (2) is approximately rectangular with rounded edges. The long axes (X) of each element (2) are preferably oriented perpendicular to the direction of travel (Y) of the batt. The geometric arrangement of the engraved elements (2) preferably consists of repeating unit cells of this form where the distance, d, is between 2 and 10 mm more preferably 3 and 8 mm. Preferably, each engraved element has a length to width ratio of more than one, most preferably within the range of 1:1 -1:4. The vertical spacing between engraved elements, s, is preferably between 1 to 10 mm, more preferably 2 to 8 mm and most preferably between 2 and 6 mm. Preferably, the depth of each engraved element is between 1 to 10 mm, more preferably 2 to 10 mm and most preferably 3 mm and 10 mm.

[0042] With reference to Fig.2 it can be seen that the roller surface (10) has projecting embossing elements (20) that have dimensions required to produce the embossed features as described in Fig. 1. The length of individual embossed elements (20) was 24 mm and the width of embossed elements (2) was 8 mm. The total compressed area using the pattern in Figure 2 was 52 % of the total area.

EXAMPLES

[0043] Example 1

[0044] A staple fibre blend of 82% mechanically recycled (pulled) acrylic textile fibre originating from post-consumer waste clothing and 18% recycled waste polypropylene fibre (mean fibre length = 40mm, density = 0.92g/cm3) was prepared. The blend was formed in to a drylaid batt by means of airlaying as follows. The fibres were first mechanically separated and dispersed into a volume of air with a high dilution ratio to maintain their separation. The air-fibre dispersion was then transported to a permeable conveyor whereupon the fibres were deposited to enable batt formation. The airlaid batt was then conveyed in to a thermal bonding oven (Using a 4 zone oven at air temperature of 185 C).

After the oven, the batt was then introduced in to the nip of a pair of unheated calender rollers. To simulate the effect of engraving one roller surface, an engraved metal screen was introduced on one side of the incoming batt after the thermal bonding oven, such that its engraved pattern was transferred to it.

The screen was engraved with a periodic geometric pattern as indicated in Figure 2.

[0045] A sample of identical composition was also made using a smooth roller such that the entire area was compressed. All other manufacturing conditions were identical. Each sample was then tested to obtain tensile properties (Table 1). The fabric tensile strength was obtained based on standard methodology (iSol 39341:2013).

Table 1

Standard Example 1

(18% by weight Polypropylene, (15% by weight Polypropylene, 100% compression area) 52% compression area) Strength (N) __________ Tensile Strength (N) __________ Tensile Tensile Burst Tensile Tensile Burst (MD) (CD) ________ (MD) (CD) _______ 82N 68N 172N 88N 69N 181N 78N 65N 201N 91N 65N 193N 85N 73N 166N 79N 66N 178N 88N 66N 162N 93N 62N 189N [0046] The results in Table 1 indicate that the reduction of polypropylene content to 15% by weight from 18% by weight does not reduce the pad strength if the sample is embossed. In Table 1, MD = machine direction and CD= cross direction in the pad. Tensile and burst strength are indicated in Newtons. If the polypropylene content is decreased from 18% by weight to 15% by weight, failure to emboss reduces the tensile strength by 30 -40%.

[0047] Example 2

A staple fibre blend of 82% mechanically recycled (pulled) acrylic textile fibre originating from post-consumer waste clothing and 18% recycled waste polypropylene fibre (mean fibre length = 40mm, density = 0.92g/cm3) was prepared. The blend was formed in to a drylaid bait by means of airlaying as follows. The fibres were first mechanically separated and dispersed into a volume of air wiih a high diluuon rauo 10 maintain their separation. The air-fibre dispersion was then transported to a permeable conveyor whereupon the fibres were deposited to enable bait formauon. The airlaid bati was then conveyed in io a thermal bonding oven (a 4 zone oven at air temperature of 185cc.). After the oven, the batt was then introduced in to the nip of a pair of unheated calender rollers operating with a pressure of approximately 10 bar.

[0048] Example 3

A staple fibre blend of 82% mechanically recycled (pulled) acrylic textile fibre originating from post-consumer waste clothing and 18% recycled waste polypropylene fibre (mean fibre length = 40mm, density = 0.92g/cm3) was prepared. The blend was formed in to a drylaid batt by means of airlaying as follows. The fibres were first mechanically separated and dispersed into a volume of air with a high dilution ratio to maintain their separation. The air-fibre dispersion was then transported to a permeable conveyor whereupon the fibres were deposited to enable batt formation. The airlaid batt was then conveyed in to a thermal bonding oven (a 4 zone oven at air temperature of 185 t.). After the oven, the batt was then introduced in to the nip of a pair of unheated calender rollers operating with a pressure of approximately 10 bar.

[0049] Example 4

[0050] In this Example the bait was compressed prior to entering the oven. A staple fibre blend of 82% mechanically recycled (pulled) acrylic textile fibre originating from post-consumer waste clothing and 18% recycled waste polypropylene fibre (mean fibre length = 40mm, density = 0.92g/cm3) was prepared. The blend was formed in to a drylaid batt by means of airlaying as follows. The fibres were first mechanically separated and dispersed into a volume of air with a high dilution ratio to maintain their separation. The air-fibre dispersion was then transported to a permeable conveyor whereupon the fibres were deposited to enable batt formation. Prior to entering the oven, a metal mesh screen was placed upon the airlaid batt, and pressure was applied during the batt's passage through the oven (a 4 zone oven at air temperature of 185°C).

Claims

CLAIMS1. A pad form material comprising embossed thermoplastic bound fibre based material, the material pad having interconnected regions of high density thermoplastic bound fibre based material defining isolated regions of low density thermoplastic bound fibre based material.
2. A pad form material comprising embossed thermoplastic bound fibre based material, the material pad having regions of high density thermoplastic bound fibre based material isolated within interconnected regions of low density thermoplastic bound fibre based material.
3. A pad form material according to claims 1 or claim 2 wherein there is a continuum of material between the high and low density regions within the material pads.
4. A pad form material comprising regions according to both claim 1 and claim 2.
5. A pad form material according to any one of the preceding claims wherein the thermoplastic bonding has been introduced via thermoplastic binding fibres.
6. A pad form material according to claim 5 wherein the thermoplastic binding fibres are made from polyolefin and/or polyester.
7. A pad form material according to claim 6 wherein the polyolefin is mechanically recycled polypropylene.
8. A pad form material according to any one of the preceding claims wherein the tensile strength is greater than 75N.
9. A pad form material according to any one of the preceding claims wherein the mean burst strength is greater than 1 75N.
10. A pad form material according to any one of the preceding claims wherein the mean weight of the pad is from 300 to 2500 g/m2.
11. A pad form material according to any one of the preceding claims wherein the pad has a mean thickness of 3 to 20 mm.
12. A pad form material according to any one of the preceding claims wherein the pad has a mean density of 50 to 300 kg/rn3.
13. A pad form material according to any one of the preceding claims wherein the regions of high density material have a mean density of greater than 150 kg/m3.
14. A pad form material according to any one of the preceding claims wherein the regions of low density material have a mean density of 150 kg/m3 or less.
15. A pad form material according to any one of the preceding claims wherein the level of thermoplastic binding fibres is less than 1 8% by weight.
16. A pad form material according to any one of the preceding claims wherein the level of thermoplastic binding fibres is from 10 to 15% by weight.
17. A pad form material according to any one of the preceding claims wherein the level of thermoplastic binding fibres is greater than 18% by weight.
18. A batt of material for the manufacture of a pad form material according to any one of the preceding claims wherein the level of thermoplastic binding fibres in the batt is from 10 to 18% by weight.
19. A batt according to claim 18, wherein the batt is thermoplastically bonded.
20. A pad form material according to any one of claims 1 to 17 wherein the total area of the pad form material that is selectively cornpressed is 90% or less.
21. A pad form material according to any one of the claims 110 17 that is composed of 100% mechanically recycled fibres obtained from post-industrial consumer waste.
22. A pad form material according to claim 20 wherein the total area of the pad form material that is selectively compressed is within the range of 30 to 80%.
23. A pad form material according to claim 22 wherein the total area of the pad form material that is selectively compressed is within the range of 35 to 65%.
24. A pad form material according to any one of claims 1 to 17 wherein the area of an individual embossed element is between 100 to 350 mm2.
25. A pad form material according to any one of claims 1 to 17 wherein the area of an individual embossed element is between 160 and 240 mm2.
26. A pad form material as claimed in any one of the preceding claims in the form of an insulator pad.
27. A method of making a pad form material, which method comprises: a) forming a fibre based batt comprising thermoplastic binding fibres; b) heating the bait to a temperature at which the thermoplastic binding fibres melt to form a thermoplastically bonded bait; c) introducing the thermoplastically bonded bait to a means for variable compression of the bonded bait, and d) passing the thermoplastically bonded batt through the variable compression means to compress the batt to form an embossed pad form material having regions of high and low density material.
28. An apparatus for manufacturng a pad form matehal, the apparatus cornpdsing: means for forming a fibre based batt corn prisng thermoplastic binding fibres; means for heafing the fibre based batt to a temperature above the mefting point of the thermoplastic binding fibres; means for transporting the thermoplastically bonded batt to and through a batt compression unit comprising means for variable compression of the batt to compress and emboss the ball and means for removal of the variably compressed batt.
29. In a further aspect the present invention provides an upholstered structure comprising one or more pad form materials according to the present invention.
30. An upholstered structure as claimed in claim 29 being selected from beds, mattresses, general furniture, sofas, armchairs, and seats.
31. An upholstered structure is claimed in claim 29 or 30 that is based on the use of spring units that provide mechanical support and recovery from compression during use of the product incorporating the pad form structure.