CA1164779A - Fibre mat for producing a three-dimensionally moulded moulding by the dry process - Google Patents
Fibre mat for producing a three-dimensionally moulded moulding by the dry processInfo
- Publication number
- CA1164779A CA1164779A CA000363727A CA363727A CA1164779A CA 1164779 A CA1164779 A CA 1164779A CA 000363727 A CA000363727 A CA 000363727A CA 363727 A CA363727 A CA 363727A CA 1164779 A CA1164779 A CA 1164779A
- Authority
- CA
- Canada
- Prior art keywords
- fibre mat
- mat according
- supporting layers
- central layer
- fibre
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B21/00—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board
- B32B21/02—Layered products comprising a layer of wood, e.g. wood board, veneer, wood particle board the layer being formed of fibres, chips, or particles, e.g. MDF, HDF, OSB, chipboard, particle board, hardboard
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B29/00—Layered products comprising a layer of paper or cardboard
- B32B29/002—Layered products comprising a layer of paper or cardboard as the main or only constituent of a layer, which is next to another layer of the same or of a different material
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form
- B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
- B32B3/266—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
- B32B5/02—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer
- B32B5/06—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by structural features of a fibrous or filamentary layer characterised by a fibrous or filamentary layer mechanically connected, e.g. by needling to another layer, e.g. of fibres, of paper
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/04—Interconnection of layers
- B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
- B32B7/04—Interconnection of layers
- B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
- B32B7/14—Interconnection of layers using interposed adhesives or interposed materials with bonding properties applied in spaced arrangements, e.g. in stripes
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M17/00—Producing multi-layer textile fabrics
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
- D06M23/00—Treatment of fibres, threads, yarns, fabrics or fibrous goods made from such materials, characterised by the process
- D06M23/14—Processes for the fixation or treatment of textile materials in three-dimensional forms
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06N—WALL, FLOOR, OR LIKE COVERING MATERIALS, e.g. LINOLEUM, OILCLOTH, ARTIFICIAL LEATHER, ROOFING FELT, CONSISTING OF A FIBROUS WEB COATED WITH A LAYER OF MACROMOLECULAR MATERIAL; FLEXIBLE SHEET MATERIAL NOT OTHERWISE PROVIDED FOR
- D06N7/00—Flexible sheet materials not otherwise provided for, e.g. textile threads, filaments, yarns or tow, glued on macromolecular material
- D06N7/0005—Floor covering on textile basis comprising a fibrous substrate being coated with at least one layer of a polymer on the top surface
- D06N7/0007—Floor covering on textile basis comprising a fibrous substrate being coated with at least one layer of a polymer on the top surface characterised by their relief structure
- D06N7/0026—Floor covering on textile basis comprising a fibrous substrate being coated with at least one layer of a polymer on the top surface characterised by their relief structure obtained by moulding, e.g. moulding table (tapis moule)
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- D—TEXTILES; PAPER
- D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
- D06Q—DECORATING TEXTILES
- D06Q1/00—Decorating textiles
- D06Q1/04—Decorating textiles by metallising
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
- B32B2260/02—Composition of the impregnated, bonded or embedded layer
- B32B2260/021—Fibrous or filamentary layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
- B32B2260/02—Composition of the impregnated, bonded or embedded layer
- B32B2260/028—Paper layer
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B2260/00—Layered product comprising an impregnated, embedded, or bonded layer wherein the layer comprises an impregnation, embedding, or binder material
- B32B2260/04—Impregnation, embedding, or binder material
- B32B2260/046—Synthetic resin
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R13/00—Elements for body-finishing, identifying, or decorating; Arrangements or adaptations for advertising purposes
- B60R13/02—Internal Trim mouldings ; Internal Ledges; Wall liners for passenger compartments; Roof liners
Abstract
ABSTRACT OF THE DISCLOSURE
The invention provides fibre mat for producing three-dimensionally moulded mouldings for example, for use as the internal lining of motor vehicles by means of the dry process, comprising a prestrengthened layer containing cellulose or lignocellulose fibres and deformable supporting layers with which the fibrous layer is joined, characterized in that the fibrous layer is arranged as the central layer between two supporting layers and that the supporting layers comprise creped, low-extension or extension-proof foil materials joined to the central layer surfaces, whilst maintaining the pulling out properties of the creping.
The invention provides fibre mat for producing three-dimensionally moulded mouldings for example, for use as the internal lining of motor vehicles by means of the dry process, comprising a prestrengthened layer containing cellulose or lignocellulose fibres and deformable supporting layers with which the fibrous layer is joined, characterized in that the fibrous layer is arranged as the central layer between two supporting layers and that the supporting layers comprise creped, low-extension or extension-proof foil materials joined to the central layer surfaces, whilst maintaining the pulling out properties of the creping.
Description
7 ~ 9 The ~nverltion relates to ~ fibre mat f~r producing a three-dimension~lly, moulded moulding by the dry proces~.
It IS known to produce three-dimensionally moulded mouldings ~xom lignocellulose fibrous materials by loosely sprinkling onto an endless con~eyor belt the fibres ~etted with small binder quantities, levelling the height of the fibre layer a~plied by a pairing roller and subsequently prestrengthening the ~ibre lay~er between pairs of rollers.
This leads to a sheet-like endless extrudate which can be cut into individual sheets from which flat blanks arQ pro-duced following Intermediate transport. Following vapour coating of the blanks, they are placed in a compression mould and are moulded into the final moulded articles, accompanied by the curing of the binder (DAS 1,224,949). The individual sheets cut in this way initially have a low deformability and limited breaking strength. Following the vapour cGating necessary for increasing the deformabllit~ for producing the three-dimensionally moulded moulding articles, the sheets no longer have a significant internal cohesion and must therefore be very carefully treated and transported. Due to their limited fibre cohesion in the steam-treated state, they can only be further shaped to a limited extent without there being thinning of the material areas tensile stressed during moulding, with the loss of fib~e cohesion and the tearing ~ of the mat.
..~' :xi 116~77g To obviate this pxoble~, it is known (DOS 1,453, 4161 to apply to the fihre mat a reinforcing fa~ric ~hich can be deformed ~ stretching and which is pressed into the fibre la~ex ~y the rollers used for prestrengthening the mat.
Here aga~n, the bond between the reinforcing fabric and the fi~re mat ~s largely lost ~hrough the vapour treatment necessary prior to the final shaping. Thus, during the moulding process necessarily considera~le relative movements occur between the individual fibres, which can bring about the tearing o~ the fibre mat.
GerrQan patent 2,364,025, also discloses a fibre mat comprising two lignocellulose fibrous layers between which is placed in f~rmly adhering manner a supporting layer~
The pre-moulded fibre mat has a plurality of regularly dis-tributed zones of limited cross-section. This improves the adhesion of the supporting layer during vapour treatment, ~o that the tensile stresses occurring during moulding can be better distri~uted in the mat. In addition, such a mat extrudate can be wound onto a reel following prestrengthening, which facilitates handling and transportation.
In order to permit the manufacture of particularly thin-walled, three-dimensional moulded mouldings, such as are for example ~e~ulxed for the internal lining of motor vehicle intexiors, a process ~s used (German Patent 2,338, 650~ ln which the fibre mat is gradually moulded in a mould e~uipped ~ith a plurality ~f foxce plugs which can be 1 16~7~9 operat~d in tim~ se~uence. T~is gradual Inoulding i~ necessary to prevent tearIng of the f~b~e mat. In this process, the fibre mat ~s gradu~ fed to the deformation points without there being an~ tearing af the fibreS. This known process used in the three-d~mensional shap~n~ of thin-walled mouldings re-quires especially careful application due to the sensitivity of the fibre mats and also re~uires a large amount of time due to the gradual, successive ~oulding.
~ further disadvantage of the known process is that the fibre mats mustbe made from top-quality wood fibre mat-erials if they are to have satisfactory deformation character-istics, particularly in connection with the necessary small wall thickness of the mouldings. It is impossible to pass below a lower fibre length limit if the tearing of the fibre mat is to be avoided during deformation. It is therefore impossible to use shorter fibres, such as are for example ob-tained in the preparation of waste materials, for example waste paper, although said waste materials have completely satisfactory material characteristics, particularly in the case of the admixture of longer length fibres.
The problem of the invention is to obviate the disadvantages inherent in the known fibre mats and their processin~ processes in such a way that a fibre mat is obtained which, in the manner of a deep drawing process, can be im-mediately moulded to a thin-walled moulding without the hitherto necessar~
gradual moulding procedure. Furthermore, through the addition of short-fibre waste material a higher strength, smaller wall thick-ness moulded article can be obtained.
According to the present invention there is provided a fibre mat for producing three-dimensionally moulded mouldings, by means of the dry process, comprising a prestrengthened layer containing cellulose or lignocellulose fibres and deformable sup-porting layers with which the fibrous layer is joined, character-ized in that the fibrous layer is arranged as the central layer between two supporting layers and that the supporting layers comprise creped low-extension or extension-proof foil materials joined to the central layer surfaces, whilst maintaining the pull-ing out properties of the creping.
The term "creping" is understood to mean all shapi~g processes to the supporting layer which increase the surface area thereof without stretching or extending the actual material when it is pulled out in at least one direction. Such shapes can be in the form of parallel folds such as pleats and this is advanta-geous if a substantially groove-likel three-dimensional shaping is desired. In the case of cup-shaped shaping crossing folds are recommended. The term "creping" also covers, for example, circular folds or impressions and in the case of fabrics those yarns which are crimped or overtwisted.
The advantage of the rnats according to the invention is initially that the fibre layer no longer comes into contact with the mould members. Thus, the sliding characteristics of the mats according to the invention during moulding are improved in the same way as the separation characteristics ater moulding. This improves the surface properties of the finished parts. In addi-tion, during the mould closing process, ~a 4 _ 1 ~6~779 the flb~au~ la~er can be thexmall~ insulated from the mouldSurface$~ so th~t there is n~ premature curing of the fibrous layer Sur~aces. This improveS the strength characteristics of the fibxous layer.
The two-side~ covering o~ the fibrous layer with supporting layers increases the effective interface between the fibxous layer and the supporting layer. This in itself considerabl~ improves the reaction of the favourable defoxmation behav~our of the $uppoxting layers on the fibrous layer. An additional important advantage is provided in this connection by the creping of the supporting layers according to the invention. The prior art, elastically defonEble sup-porting layers, can be extended up to failure, i.e. they cover the surface requirement necessary for three-dimensional deformation and become thin during déformation. Within the scope of their elasticity, they are initially randomly extensible, the extension being distributed in an uncontrolled manner over tne entire surface area. Since it is necessary to avoid in the fibrous material local extensions which are greater than the covering or overlapping length of the fibres, the cooperation between the prior art elastic supporting layers and the fibxous layer means that locally the extensibility of the fibrous layer can be exhausted. This considerably reduces the possibility of shaping fibre mats with supporting layers according to the prior art. ~s opposed to this, creped suppoXting la~ers have the suxface reserye neceSsary fox ; shaping ~ithin the actual cxep~ng and need not cover it by a thickne~s. 1QSS. ~f the $urface xe$e~Ye of the creping i$
locall~ u~ed up~ te~sile st~es~es ~re ~uh~e~uentl~v txansfexxed.
~nto the adjacent area$ and their surfacç reserye is also utilized, The shape and ~nten$~ty of the creping can be selected in the way that the local extensibility necessary for shaping - 5 ~
1 16~77g is ensux~d a,nd the l~c~l extensibility of the sU~po~ting la,~ex can be ~d~pted to the cavering length of the fibres.
This prevents a local failure of the fibrous layer.
The laxge ~uxface area of the ~upporting layers in the creped state also a~dS the force transfex to the interface between the fibrous layer and the supporting layer. Thus, a mat is formed which is able during deformation to transfer significant tensile stresses, even in the outer area, without the local failure of the fi~rous la~er.
The reduction of the stretching proportion in the overall mat deformation means a more uniform thickness distri-bution in the finished article. This gives the particularly advantageous , possi~ility of producing members, whose wall thickness is much less than that of ~he hitherto produced members. In the prior art, a finished article thickness of approximately 2mm is considered to be the lower limit of what ~' is technically possible. By means of the mats according to the invention, it is possible to produce finished products with a satisfactory quality and wall thickness of only approximately lmm.
As the increase in the surface area of creped supporting layers only requires forces during moulding, it is possible to use higher strength supporting layers for the mats according to the invention. The moulded article then has a sandwich structure comprising a medium-strength core and high-strength coVexing layers. Th,e xesultin~ improVement to the stxength a,nd xigid~ty of the fini~shed pxoducts makes it pOS-sible to pxQduce the latter with thinner w~lls and thexefoxe moxe ady~ta~geously~ fxo~ the mater;~al and cost standpoint than 3Q in t~e pri~or art, wh~lst pxo~d~ng the ~same use cha~acter,istics.
; The.'twQ-sided covexing of the fibre mat with closed suppoXt~ng laxers also reduces the risk of damage to the mats '7 7 9 dur~ng t~nsport~tion ~nd handlin~.
ThiS is p~rticularl~ important if thin-walled finished articles axe sought, so that the fibxe mats have only a limited thickness and consequentl~ l~mited inherent stability. The two-sided suppoxting layer ~n particular considerably reduces the ~racture risk of thin fibre mats during transporta-~ion.
The advantageous possibility of reaucing by about a half the wall thickness of the ~inished articles through the use of the mats according to the invention will now be de-scribed aga;n ~n general terms.
Quite apart from the weight and material saving of 50% the necessary overall moulding time is reduced to approx-imately half. The moulding time when moulding wood fibre mat-erials is mainly due to the inadequate thermal conductivity of this material group. A thickness reduction means a cor-respondingly faster thorough heating (in practice this means fixed moulding times/millimetre of material). This makes it possible to increase the utilization rate of the investment-in-tensive large compression presses and can be increased in thesame porportion as the number of necessary cost-intensive moulds can be reduced. Thus, considerable rationalization can be ob-tained with the mats according to the invention.
The punctiform or linear, fixed joining of the sup-porting layers to one another at preferably regular intervals in accoxdance with the invention additiona,lly improves the over-all cha~a~cte~istics of the mat. This brings about a reciprocal limita,tion of the ftbXous la,ye~ a~e,a,s, which can only be in-te,rnal~y di~s,pl~ced but ar,e xec~pxoc,a,lly ~xed on a laxger ~ea 3Q ~as~s. Th~s o~yiates the ~sk o~ l~rge~ areas displacemen~s of the ,f~,bxou~ mats duri;ng the mould~n~ process~ so that during the de~ormation of the mat a more uniform material distribution X
1 ~6~779 is a~chieyed~ This'ef~ect is ~oughly cqm~axable ~ith the be-hqv~oux of mode~ punct~oxm o~ l~near quilted eiderdown$ whexe a uniform distribution o~ t~e fllling is still ensured if the eidexdow~ ~s shook ox rolled up.
~ ccording to an ad~anta~geous further development of the invention, the supporting la~er creping is a cross-creping.
This leads to an improved deformability of these layers.
It may also be advantageous if the supporting layers are perforated (e.g. by needling~. The perforation makes the supporting layers gas-permeable,,so that the mats according to the invention can easily be thermally treated, e.g. with steam.
The gas permeability resulting from the perforation also aids the extraction of moisture from the mat during moulding.
As the deformation characteristics of the supporting layers need no longer be provided by the actual material and instead result from the creping, all crepable materials can be used for the supporting ~ayers for the mats according to the invention.
Crepéd fabrics made from natural or synthetic fibres can be used in the same way as creped plastic foils. Supporting layers of creped metal foils are also possible, particularly if the finished article must have a maximum resistance to mois-ture action. Supporting layers made from creped paper can be used with particular advantage, because this material can be inexpensively obtained and is easily processed. Fibre mats a,ccoxding ta the invention can also have creped Supporting la~ers made from~'different matexiql,s on the top and bott~m of the mat. Th~s makes it possible, e,g~ to provide the visible ~de a,f, t~e ~n~s,hed axt~cl,e ~th a, s~U~porting layer selected ,, 3Q on thq ~7als,i~s: o,~ decorative ~s~t~ndpo~ntsl ~hilst the su~poXting l~ex used on t~e s,~de which ~s not v~$ible ~$ selected onl~ on the ba~s~s of cost standpoints.
- 8 _ .
~ f ,im~xe~n~ta~ble suppo,rting l~ers are used it can be pa~ticul,a~ly ad~antageous ~ox them to contain a thermosettin~, duroplast~c ,r:es~n. ~lso the~ ca,n, for example, be preimpre~
nated ~ith ~henolic or melamine ~esins. Thus, during hot mould~ng, A hi~H-finish, high-~tren~th surface layer is obtained giving the flnished article sandwich chaxacteristics.
This is parLicularly advantageous when moulding thin-walled articles.
Unlike in the prior art used as a basis for the inven-tion and where the supporting layers used firmly adhere bytheir entire surface area to the fi~rous layer, it is not always necessary with the ~ats according to the invention for there to be a whole-area, firm adherence with the supporting layers.
As a result of the punctiform or linear interconnec-tion of the supporting layers, areas are formed in which the fibrous layer is adequately fixed between the supporting layers.
For special shaping problems, such a mat construction can be advantageous. However, it is generally preferable to fix the entire surface area of the supporting layers to the fibrous layers by means of an adhesive. This improves the force initiation conditions for the necessary re-shaping forces.
The adhesive used for this purpose can be adhesives acting in a thermoplastic manner. However, it is also possible to use contact or solvent adhesives. It is particularly economic and advantageous from the manufacturing standpoint if the sup-porting layers are precoated with the adhesive used.
The joining together of, the supporting layers in punctifo~m or linear manner a,ccord~ng to the inVention can take pla,ce by known textile aids~ e,g. by sewing or stitching.
It is,more a,dv,a,ntageous from the production standpoint if the puncti~o~m or linear ~nterconnection of the supporting layers is brought about by adhesion. In this case, the corresponding _ g _ 7 ~
adhesive joints o~ the suppa~ting l~exs ~e produced b~ the adhesive used ~or br;nging about the whole~area adhesion o~ the supporting l~er to the fibrous layer. This is the best solu~
ti~n from the production and cost standpoints.
Like the fibre m~ts according to the prior art, the fibre mats accordin~ to the invention are preferably provided with thexmosetting ~lnders and are mainly hot~moulded to moulded articles. In this case, it is particularly advantageous if the punctiform ox linear connections between the individual sup-porting layers are made in such a way that the connection pointsor lines are dissolved in the mould heat.
During the closing of the compression mould the con-necting points still exercise the hitherto described functions.
However, after intense contact with the mould surfaces during the building up of the moulding pressure, the connecting points dissolve and permit a material exchange in these local areas, I
so that the connection points or lines can no longer be seen on the finished article. If the supporting layers are joined together by textile processes, the solubility in heat - 20 can be brou~ht about through using thermoplastic stitching threads. In the case of adhesive joints, the joining strength can be eliminated in the heat by using adhesives whose binding force decreases in the presence of heat.
~ n important advantage of mats according to the inven-tion is that their deformation characteristics is no longer preponderantly determined by the qualit~ of the fibrous materials used. Thus, e.~. in the p~ioX axt mats it is not possible or is only possible to a limited extent to concomitantly use p~oduçtion ~,a~Ste, because during the preparation of the latter the fib~e ~eng~ is ~educed and qn add~tion of t~eated production ~aste con~sidexabl~ ~mpa,ixs the deform~tion char~cteristics of the mat. In the case of the mats according to the invention, - lQ -;1,, the de~o~mation ~roperties o.the $u~portin~ la~ers pxedo~inate.
Thus, lt ~s poss.~ble to u~e producti~n waste, including pro-cessed sup~o~txng laye~s in the production of mats, thexeby ensur~ng an ~nexpensive ~aste-free production, which saves raw materials.
The central layers of these mats are pre-strengthened, but in the initial state have a much lower density than in the moulded state. The deformabilit~ of the central layers is im-proved by thermal action, e.g. steam treatment prior to mould-ing. If they are to be adequately deformable, they must havea moisture content a~ove 10%. This is a disadvantage from the moulding standpoint,. because moisture extraction during the hot final moulding process requires additional moulding time.
During moulding, the moisture content can lead to ! steam bubble for~ation, particularly if steam-impermeable sup-porting layers are used. The perforation of the supporting layers proposed for the purpose of eliminating this disadvantage also fail~ to completely eliminate the risk of steam bubble . formation, because the perforated proportion of the overall surface area of the supporting layers is naturally small. Steam bubble formation either leads to an increased quantity of waste material or requires a correspondingly complicated moulding procedure serving for the elim~nation thereof (intermediate relief of the press during the moulding o~ the final article~
if these factors reduce the economy of the overall process.
Thus, according to an advantageous further development of the ~nVention, the densit~ of the pre-strengthened central la~e~ pr~aX to moulding ap~roximatel~ corresponds to its density in the ~ s.~h.ed axt~cle/ th.e mo~stu~e level thereof heing below lQ~
Th.:e low moistuXe content ~nitially has the advantage that the moulding ti.me can ~e further reduced and that steam .
1 :~6~7 ~9 bubbles do not occur in the moulded ~article, As the densit~
of the p~eStrengthened central layer corresponds appxoximatel~
to that 4f the finished art~cle, said layer has only a limited tendenc~ to uncontrolled moisture absorption during inter-mediate storage, so that ~ts preconditioning can be maintained over a relatively long period. Further advantages result from the fact that mats w~th central layers compressed to this extent axe less voluminous a,nd consequently required less storage space. In addition, their handling and transportation stability is considerably improved compared with known mats.
The central layers of mats according to the invention must also have adequate deforma~ilit~ in correspondingly, highly compressed state, which generally requires additional measures. Thus, for example, according to an advantageous em-bodiment the central layer of such mats comprises at least one sheet of creped paper or cardboard impregnated with thermo-; plastic or duroplastic binders., The entire surface area of creped papers, cardboard, woven or non-woven fabrics is uniformly finely folded. Such structures consequently have an overall surface area which is a multiple of that corresponding to the external dimensions of the corresponding webs. They are there-fore able to co~er the increase in the surface area required for producing the three-dimensional shape from the "stored sur~ace area" qf the pleating (crepin~. In the case of a suitable shape of the crepxng folds (cross-creping in which the cox~esponding web is finel~ folded ~in two directions at right angles to one another), the corresponding material has a high defo~a,b~l~t~ ~n all the d~,~ect,ions in questian. The increase in the s,u~ace ,a,rea 2S m,a,de po~ble b~ $m~othing the folds, without the ~a~e~ e~ng suhject to higher ten~ile stresses resultinq fxom the deformati~n. ThuS, the creping of the centra,l la~e~ permitsthe necessar~ deformation thereof and , JI
7 7 g creped pape~s which have alxeady xeached their ~in~l density can be prefabxicated and ~mpregnated without di~ficulty. They can contain pulverulant fillers ~n addition to cellulose fibres.
Textile central la~ers can also be used for producing mats according to the invention. Thus, for example, it is possible for the central layer to comprise at least one sheet of creped fabric or non-woven fabric impregnated with duro-plastic or thermoplastic binders. Here again, the necessary deformaBtlity of,the central la~er is obtained by impregnating the per se inadequately deforma~le woven or non-woven fabric. ~, Particularly favourable conditions are provided if adequate deformability is ensured on the basis of the material used for'the central layer of the mats. This is for example the case if the central layer is a thermoplastic material filled and/or reinforced preferably with cellulose or lignocellulose materials. Such a mat can be hot-moulded without taking special precautions. Particular advantages are obtained in connection with moulded articles which are to be exposed to thermal stress-ing in subsequent use if the creped supporting layers are made from metal. This improves both the dimensional stability of the articles in heat and also reduces the heat absorption due to the favourable reflection conditions of the supporting layer. I
Creped papers, cardboards, fabrics, woven or non-woven fabrics impregnated with binders, as proposed for the centxal layer m~terial of the mats according to the inVention can onl~ be creped in a limited thickness. According to a further development ~f the inventiVe principle, it is therefore advant~geous ~ use cent~al laxe~s~ compxising ,an intexla~inar bond ~ ~ne X more mater~a,ls o~ t~e descxibed type, The in-3Q diy~du~ e~t~ o~ the centx~l la~e~ c~n then be joined bysewing, $t~tch~ng or needling~
This can in particular be advantageous if the indi-Xl vidual sheets aXe ~or~ed fro~ p~pex, c~xdboard, ~oyen or non-wo~en fabrics~ If textile ~oininy processes are used, it is advantageous ~or the joininy threads to be made from thermo-plastic ~aterials, which are ~eadily deformable during hot-moulding. A further advantageous possibility of constructing the core layer as an interlaminar bond is brought about by producing the latter by an adhesive which softens in the presence of heat.
This procedure has the advantage that the central layers can be bullt up in random thickness from individual layers with good deformation c~aracteristics, whose recipro-cal joint becomes flexible during hot moulding, so that the de-formation characteristics of the individual layers can be fully utilized.
Due to the fact that in the interlaminar bond, the materials can be combined virtually at random, further adap-tation scope is obtai~ned for the chaxacteristics of the moulded article.
Central layers according to the invention can be wholly or partly produced from recycled materials. The creped papers or cardboards of the central layers can for example be recycled papers or cardboards, whose qualities are inadequate -for other uses. This also applied to non-woven fabr~cs or woven fabxlcs made from synthet~c an~or natuxal fibres. In both casesl the primary products for producing the mats accord-in~ to the invention can be obtained fxom the appropriate in-dustxy.
~ t is also possible to prQduce the central layers fxom fil~ed ~d~ox xe~nf~rced t~exmoplastic ~aterials using low-~x~d~ thermQplastic mate~ial ~a,~t~, such as is e.g. obtained in the foxm of coated papex w~ste ~nd cable industry waste and which cannot be used for other purposes. Colour differences 1 1~4'~79 and impuritXes do not pla~ an ~mpo~tant part in connect,i,on with the use ,a,ccording to the invention. Inadequate mechanical stxength ch~racteristics, such as can occur when using mixed waste, can be compensated by a suitable selection of the $upporting layers.
The mats according to the invention are produced on the basis of the prior art. The central layer is applied to the lower supporting layer which serves as the conveyor belt.
The upper supporting layer is then supplied from a reel and the assembly formed by the supp~rting layers and the central layer is passed between the pairS of rollers used for prestreng-thening and said layers are joined together. The perforations can be obtained by pairs of rollers provided with corresponding needles, wh~ch in each case pass through a supporting layer and partly penetrate the central layer.
X!
It IS known to produce three-dimensionally moulded mouldings ~xom lignocellulose fibrous materials by loosely sprinkling onto an endless con~eyor belt the fibres ~etted with small binder quantities, levelling the height of the fibre layer a~plied by a pairing roller and subsequently prestrengthening the ~ibre lay~er between pairs of rollers.
This leads to a sheet-like endless extrudate which can be cut into individual sheets from which flat blanks arQ pro-duced following Intermediate transport. Following vapour coating of the blanks, they are placed in a compression mould and are moulded into the final moulded articles, accompanied by the curing of the binder (DAS 1,224,949). The individual sheets cut in this way initially have a low deformability and limited breaking strength. Following the vapour cGating necessary for increasing the deformabllit~ for producing the three-dimensionally moulded moulding articles, the sheets no longer have a significant internal cohesion and must therefore be very carefully treated and transported. Due to their limited fibre cohesion in the steam-treated state, they can only be further shaped to a limited extent without there being thinning of the material areas tensile stressed during moulding, with the loss of fib~e cohesion and the tearing ~ of the mat.
..~' :xi 116~77g To obviate this pxoble~, it is known (DOS 1,453, 4161 to apply to the fihre mat a reinforcing fa~ric ~hich can be deformed ~ stretching and which is pressed into the fibre la~ex ~y the rollers used for prestrengthening the mat.
Here aga~n, the bond between the reinforcing fabric and the fi~re mat ~s largely lost ~hrough the vapour treatment necessary prior to the final shaping. Thus, during the moulding process necessarily considera~le relative movements occur between the individual fibres, which can bring about the tearing o~ the fibre mat.
GerrQan patent 2,364,025, also discloses a fibre mat comprising two lignocellulose fibrous layers between which is placed in f~rmly adhering manner a supporting layer~
The pre-moulded fibre mat has a plurality of regularly dis-tributed zones of limited cross-section. This improves the adhesion of the supporting layer during vapour treatment, ~o that the tensile stresses occurring during moulding can be better distri~uted in the mat. In addition, such a mat extrudate can be wound onto a reel following prestrengthening, which facilitates handling and transportation.
In order to permit the manufacture of particularly thin-walled, three-dimensional moulded mouldings, such as are for example ~e~ulxed for the internal lining of motor vehicle intexiors, a process ~s used (German Patent 2,338, 650~ ln which the fibre mat is gradually moulded in a mould e~uipped ~ith a plurality ~f foxce plugs which can be 1 16~7~9 operat~d in tim~ se~uence. T~is gradual Inoulding i~ necessary to prevent tearIng of the f~b~e mat. In this process, the fibre mat ~s gradu~ fed to the deformation points without there being an~ tearing af the fibreS. This known process used in the three-d~mensional shap~n~ of thin-walled mouldings re-quires especially careful application due to the sensitivity of the fibre mats and also re~uires a large amount of time due to the gradual, successive ~oulding.
~ further disadvantage of the known process is that the fibre mats mustbe made from top-quality wood fibre mat-erials if they are to have satisfactory deformation character-istics, particularly in connection with the necessary small wall thickness of the mouldings. It is impossible to pass below a lower fibre length limit if the tearing of the fibre mat is to be avoided during deformation. It is therefore impossible to use shorter fibres, such as are for example ob-tained in the preparation of waste materials, for example waste paper, although said waste materials have completely satisfactory material characteristics, particularly in the case of the admixture of longer length fibres.
The problem of the invention is to obviate the disadvantages inherent in the known fibre mats and their processin~ processes in such a way that a fibre mat is obtained which, in the manner of a deep drawing process, can be im-mediately moulded to a thin-walled moulding without the hitherto necessar~
gradual moulding procedure. Furthermore, through the addition of short-fibre waste material a higher strength, smaller wall thick-ness moulded article can be obtained.
According to the present invention there is provided a fibre mat for producing three-dimensionally moulded mouldings, by means of the dry process, comprising a prestrengthened layer containing cellulose or lignocellulose fibres and deformable sup-porting layers with which the fibrous layer is joined, character-ized in that the fibrous layer is arranged as the central layer between two supporting layers and that the supporting layers comprise creped low-extension or extension-proof foil materials joined to the central layer surfaces, whilst maintaining the pull-ing out properties of the creping.
The term "creping" is understood to mean all shapi~g processes to the supporting layer which increase the surface area thereof without stretching or extending the actual material when it is pulled out in at least one direction. Such shapes can be in the form of parallel folds such as pleats and this is advanta-geous if a substantially groove-likel three-dimensional shaping is desired. In the case of cup-shaped shaping crossing folds are recommended. The term "creping" also covers, for example, circular folds or impressions and in the case of fabrics those yarns which are crimped or overtwisted.
The advantage of the rnats according to the invention is initially that the fibre layer no longer comes into contact with the mould members. Thus, the sliding characteristics of the mats according to the invention during moulding are improved in the same way as the separation characteristics ater moulding. This improves the surface properties of the finished parts. In addi-tion, during the mould closing process, ~a 4 _ 1 ~6~779 the flb~au~ la~er can be thexmall~ insulated from the mouldSurface$~ so th~t there is n~ premature curing of the fibrous layer Sur~aces. This improveS the strength characteristics of the fibxous layer.
The two-side~ covering o~ the fibrous layer with supporting layers increases the effective interface between the fibxous layer and the supporting layer. This in itself considerabl~ improves the reaction of the favourable defoxmation behav~our of the $uppoxting layers on the fibrous layer. An additional important advantage is provided in this connection by the creping of the supporting layers according to the invention. The prior art, elastically defonEble sup-porting layers, can be extended up to failure, i.e. they cover the surface requirement necessary for three-dimensional deformation and become thin during déformation. Within the scope of their elasticity, they are initially randomly extensible, the extension being distributed in an uncontrolled manner over tne entire surface area. Since it is necessary to avoid in the fibrous material local extensions which are greater than the covering or overlapping length of the fibres, the cooperation between the prior art elastic supporting layers and the fibxous layer means that locally the extensibility of the fibrous layer can be exhausted. This considerably reduces the possibility of shaping fibre mats with supporting layers according to the prior art. ~s opposed to this, creped suppoXting la~ers have the suxface reserye neceSsary fox ; shaping ~ithin the actual cxep~ng and need not cover it by a thickne~s. 1QSS. ~f the $urface xe$e~Ye of the creping i$
locall~ u~ed up~ te~sile st~es~es ~re ~uh~e~uentl~v txansfexxed.
~nto the adjacent area$ and their surfacç reserye is also utilized, The shape and ~nten$~ty of the creping can be selected in the way that the local extensibility necessary for shaping - 5 ~
1 16~77g is ensux~d a,nd the l~c~l extensibility of the sU~po~ting la,~ex can be ~d~pted to the cavering length of the fibres.
This prevents a local failure of the fibrous layer.
The laxge ~uxface area of the ~upporting layers in the creped state also a~dS the force transfex to the interface between the fibrous layer and the supporting layer. Thus, a mat is formed which is able during deformation to transfer significant tensile stresses, even in the outer area, without the local failure of the fi~rous la~er.
The reduction of the stretching proportion in the overall mat deformation means a more uniform thickness distri-bution in the finished article. This gives the particularly advantageous , possi~ility of producing members, whose wall thickness is much less than that of ~he hitherto produced members. In the prior art, a finished article thickness of approximately 2mm is considered to be the lower limit of what ~' is technically possible. By means of the mats according to the invention, it is possible to produce finished products with a satisfactory quality and wall thickness of only approximately lmm.
As the increase in the surface area of creped supporting layers only requires forces during moulding, it is possible to use higher strength supporting layers for the mats according to the invention. The moulded article then has a sandwich structure comprising a medium-strength core and high-strength coVexing layers. Th,e xesultin~ improVement to the stxength a,nd xigid~ty of the fini~shed pxoducts makes it pOS-sible to pxQduce the latter with thinner w~lls and thexefoxe moxe ady~ta~geously~ fxo~ the mater;~al and cost standpoint than 3Q in t~e pri~or art, wh~lst pxo~d~ng the ~same use cha~acter,istics.
; The.'twQ-sided covexing of the fibre mat with closed suppoXt~ng laxers also reduces the risk of damage to the mats '7 7 9 dur~ng t~nsport~tion ~nd handlin~.
ThiS is p~rticularl~ important if thin-walled finished articles axe sought, so that the fibxe mats have only a limited thickness and consequentl~ l~mited inherent stability. The two-sided suppoxting layer ~n particular considerably reduces the ~racture risk of thin fibre mats during transporta-~ion.
The advantageous possibility of reaucing by about a half the wall thickness of the ~inished articles through the use of the mats according to the invention will now be de-scribed aga;n ~n general terms.
Quite apart from the weight and material saving of 50% the necessary overall moulding time is reduced to approx-imately half. The moulding time when moulding wood fibre mat-erials is mainly due to the inadequate thermal conductivity of this material group. A thickness reduction means a cor-respondingly faster thorough heating (in practice this means fixed moulding times/millimetre of material). This makes it possible to increase the utilization rate of the investment-in-tensive large compression presses and can be increased in thesame porportion as the number of necessary cost-intensive moulds can be reduced. Thus, considerable rationalization can be ob-tained with the mats according to the invention.
The punctiform or linear, fixed joining of the sup-porting layers to one another at preferably regular intervals in accoxdance with the invention additiona,lly improves the over-all cha~a~cte~istics of the mat. This brings about a reciprocal limita,tion of the ftbXous la,ye~ a~e,a,s, which can only be in-te,rnal~y di~s,pl~ced but ar,e xec~pxoc,a,lly ~xed on a laxger ~ea 3Q ~as~s. Th~s o~yiates the ~sk o~ l~rge~ areas displacemen~s of the ,f~,bxou~ mats duri;ng the mould~n~ process~ so that during the de~ormation of the mat a more uniform material distribution X
1 ~6~779 is a~chieyed~ This'ef~ect is ~oughly cqm~axable ~ith the be-hqv~oux of mode~ punct~oxm o~ l~near quilted eiderdown$ whexe a uniform distribution o~ t~e fllling is still ensured if the eidexdow~ ~s shook ox rolled up.
~ ccording to an ad~anta~geous further development of the invention, the supporting la~er creping is a cross-creping.
This leads to an improved deformability of these layers.
It may also be advantageous if the supporting layers are perforated (e.g. by needling~. The perforation makes the supporting layers gas-permeable,,so that the mats according to the invention can easily be thermally treated, e.g. with steam.
The gas permeability resulting from the perforation also aids the extraction of moisture from the mat during moulding.
As the deformation characteristics of the supporting layers need no longer be provided by the actual material and instead result from the creping, all crepable materials can be used for the supporting ~ayers for the mats according to the invention.
Crepéd fabrics made from natural or synthetic fibres can be used in the same way as creped plastic foils. Supporting layers of creped metal foils are also possible, particularly if the finished article must have a maximum resistance to mois-ture action. Supporting layers made from creped paper can be used with particular advantage, because this material can be inexpensively obtained and is easily processed. Fibre mats a,ccoxding ta the invention can also have creped Supporting la~ers made from~'different matexiql,s on the top and bott~m of the mat. Th~s makes it possible, e,g~ to provide the visible ~de a,f, t~e ~n~s,hed axt~cl,e ~th a, s~U~porting layer selected ,, 3Q on thq ~7als,i~s: o,~ decorative ~s~t~ndpo~ntsl ~hilst the su~poXting l~ex used on t~e s,~de which ~s not v~$ible ~$ selected onl~ on the ba~s~s of cost standpoints.
- 8 _ .
~ f ,im~xe~n~ta~ble suppo,rting l~ers are used it can be pa~ticul,a~ly ad~antageous ~ox them to contain a thermosettin~, duroplast~c ,r:es~n. ~lso the~ ca,n, for example, be preimpre~
nated ~ith ~henolic or melamine ~esins. Thus, during hot mould~ng, A hi~H-finish, high-~tren~th surface layer is obtained giving the flnished article sandwich chaxacteristics.
This is parLicularly advantageous when moulding thin-walled articles.
Unlike in the prior art used as a basis for the inven-tion and where the supporting layers used firmly adhere bytheir entire surface area to the fi~rous layer, it is not always necessary with the ~ats according to the invention for there to be a whole-area, firm adherence with the supporting layers.
As a result of the punctiform or linear interconnec-tion of the supporting layers, areas are formed in which the fibrous layer is adequately fixed between the supporting layers.
For special shaping problems, such a mat construction can be advantageous. However, it is generally preferable to fix the entire surface area of the supporting layers to the fibrous layers by means of an adhesive. This improves the force initiation conditions for the necessary re-shaping forces.
The adhesive used for this purpose can be adhesives acting in a thermoplastic manner. However, it is also possible to use contact or solvent adhesives. It is particularly economic and advantageous from the manufacturing standpoint if the sup-porting layers are precoated with the adhesive used.
The joining together of, the supporting layers in punctifo~m or linear manner a,ccord~ng to the inVention can take pla,ce by known textile aids~ e,g. by sewing or stitching.
It is,more a,dv,a,ntageous from the production standpoint if the puncti~o~m or linear ~nterconnection of the supporting layers is brought about by adhesion. In this case, the corresponding _ g _ 7 ~
adhesive joints o~ the suppa~ting l~exs ~e produced b~ the adhesive used ~or br;nging about the whole~area adhesion o~ the supporting l~er to the fibrous layer. This is the best solu~
ti~n from the production and cost standpoints.
Like the fibre m~ts according to the prior art, the fibre mats accordin~ to the invention are preferably provided with thexmosetting ~lnders and are mainly hot~moulded to moulded articles. In this case, it is particularly advantageous if the punctiform ox linear connections between the individual sup-porting layers are made in such a way that the connection pointsor lines are dissolved in the mould heat.
During the closing of the compression mould the con-necting points still exercise the hitherto described functions.
However, after intense contact with the mould surfaces during the building up of the moulding pressure, the connecting points dissolve and permit a material exchange in these local areas, I
so that the connection points or lines can no longer be seen on the finished article. If the supporting layers are joined together by textile processes, the solubility in heat - 20 can be brou~ht about through using thermoplastic stitching threads. In the case of adhesive joints, the joining strength can be eliminated in the heat by using adhesives whose binding force decreases in the presence of heat.
~ n important advantage of mats according to the inven-tion is that their deformation characteristics is no longer preponderantly determined by the qualit~ of the fibrous materials used. Thus, e.~. in the p~ioX axt mats it is not possible or is only possible to a limited extent to concomitantly use p~oduçtion ~,a~Ste, because during the preparation of the latter the fib~e ~eng~ is ~educed and qn add~tion of t~eated production ~aste con~sidexabl~ ~mpa,ixs the deform~tion char~cteristics of the mat. In the case of the mats according to the invention, - lQ -;1,, the de~o~mation ~roperties o.the $u~portin~ la~ers pxedo~inate.
Thus, lt ~s poss.~ble to u~e producti~n waste, including pro-cessed sup~o~txng laye~s in the production of mats, thexeby ensur~ng an ~nexpensive ~aste-free production, which saves raw materials.
The central layers of these mats are pre-strengthened, but in the initial state have a much lower density than in the moulded state. The deformabilit~ of the central layers is im-proved by thermal action, e.g. steam treatment prior to mould-ing. If they are to be adequately deformable, they must havea moisture content a~ove 10%. This is a disadvantage from the moulding standpoint,. because moisture extraction during the hot final moulding process requires additional moulding time.
During moulding, the moisture content can lead to ! steam bubble for~ation, particularly if steam-impermeable sup-porting layers are used. The perforation of the supporting layers proposed for the purpose of eliminating this disadvantage also fail~ to completely eliminate the risk of steam bubble . formation, because the perforated proportion of the overall surface area of the supporting layers is naturally small. Steam bubble formation either leads to an increased quantity of waste material or requires a correspondingly complicated moulding procedure serving for the elim~nation thereof (intermediate relief of the press during the moulding o~ the final article~
if these factors reduce the economy of the overall process.
Thus, according to an advantageous further development of the ~nVention, the densit~ of the pre-strengthened central la~e~ pr~aX to moulding ap~roximatel~ corresponds to its density in the ~ s.~h.ed axt~cle/ th.e mo~stu~e level thereof heing below lQ~
Th.:e low moistuXe content ~nitially has the advantage that the moulding ti.me can ~e further reduced and that steam .
1 :~6~7 ~9 bubbles do not occur in the moulded ~article, As the densit~
of the p~eStrengthened central layer corresponds appxoximatel~
to that 4f the finished art~cle, said layer has only a limited tendenc~ to uncontrolled moisture absorption during inter-mediate storage, so that ~ts preconditioning can be maintained over a relatively long period. Further advantages result from the fact that mats w~th central layers compressed to this extent axe less voluminous a,nd consequently required less storage space. In addition, their handling and transportation stability is considerably improved compared with known mats.
The central layers of mats according to the invention must also have adequate deforma~ilit~ in correspondingly, highly compressed state, which generally requires additional measures. Thus, for example, according to an advantageous em-bodiment the central layer of such mats comprises at least one sheet of creped paper or cardboard impregnated with thermo-; plastic or duroplastic binders., The entire surface area of creped papers, cardboard, woven or non-woven fabrics is uniformly finely folded. Such structures consequently have an overall surface area which is a multiple of that corresponding to the external dimensions of the corresponding webs. They are there-fore able to co~er the increase in the surface area required for producing the three-dimensional shape from the "stored sur~ace area" qf the pleating (crepin~. In the case of a suitable shape of the crepxng folds (cross-creping in which the cox~esponding web is finel~ folded ~in two directions at right angles to one another), the corresponding material has a high defo~a,b~l~t~ ~n all the d~,~ect,ions in questian. The increase in the s,u~ace ,a,rea 2S m,a,de po~ble b~ $m~othing the folds, without the ~a~e~ e~ng suhject to higher ten~ile stresses resultinq fxom the deformati~n. ThuS, the creping of the centra,l la~e~ permitsthe necessar~ deformation thereof and , JI
7 7 g creped pape~s which have alxeady xeached their ~in~l density can be prefabxicated and ~mpregnated without di~ficulty. They can contain pulverulant fillers ~n addition to cellulose fibres.
Textile central la~ers can also be used for producing mats according to the invention. Thus, for example, it is possible for the central layer to comprise at least one sheet of creped fabric or non-woven fabric impregnated with duro-plastic or thermoplastic binders. Here again, the necessary deformaBtlity of,the central la~er is obtained by impregnating the per se inadequately deforma~le woven or non-woven fabric. ~, Particularly favourable conditions are provided if adequate deformability is ensured on the basis of the material used for'the central layer of the mats. This is for example the case if the central layer is a thermoplastic material filled and/or reinforced preferably with cellulose or lignocellulose materials. Such a mat can be hot-moulded without taking special precautions. Particular advantages are obtained in connection with moulded articles which are to be exposed to thermal stress-ing in subsequent use if the creped supporting layers are made from metal. This improves both the dimensional stability of the articles in heat and also reduces the heat absorption due to the favourable reflection conditions of the supporting layer. I
Creped papers, cardboards, fabrics, woven or non-woven fabrics impregnated with binders, as proposed for the centxal layer m~terial of the mats according to the inVention can onl~ be creped in a limited thickness. According to a further development ~f the inventiVe principle, it is therefore advant~geous ~ use cent~al laxe~s~ compxising ,an intexla~inar bond ~ ~ne X more mater~a,ls o~ t~e descxibed type, The in-3Q diy~du~ e~t~ o~ the centx~l la~e~ c~n then be joined bysewing, $t~tch~ng or needling~
This can in particular be advantageous if the indi-Xl vidual sheets aXe ~or~ed fro~ p~pex, c~xdboard, ~oyen or non-wo~en fabrics~ If textile ~oininy processes are used, it is advantageous ~or the joininy threads to be made from thermo-plastic ~aterials, which are ~eadily deformable during hot-moulding. A further advantageous possibility of constructing the core layer as an interlaminar bond is brought about by producing the latter by an adhesive which softens in the presence of heat.
This procedure has the advantage that the central layers can be bullt up in random thickness from individual layers with good deformation c~aracteristics, whose recipro-cal joint becomes flexible during hot moulding, so that the de-formation characteristics of the individual layers can be fully utilized.
Due to the fact that in the interlaminar bond, the materials can be combined virtually at random, further adap-tation scope is obtai~ned for the chaxacteristics of the moulded article.
Central layers according to the invention can be wholly or partly produced from recycled materials. The creped papers or cardboards of the central layers can for example be recycled papers or cardboards, whose qualities are inadequate -for other uses. This also applied to non-woven fabr~cs or woven fabxlcs made from synthet~c an~or natuxal fibres. In both casesl the primary products for producing the mats accord-in~ to the invention can be obtained fxom the appropriate in-dustxy.
~ t is also possible to prQduce the central layers fxom fil~ed ~d~ox xe~nf~rced t~exmoplastic ~aterials using low-~x~d~ thermQplastic mate~ial ~a,~t~, such as is e.g. obtained in the foxm of coated papex w~ste ~nd cable industry waste and which cannot be used for other purposes. Colour differences 1 1~4'~79 and impuritXes do not pla~ an ~mpo~tant part in connect,i,on with the use ,a,ccording to the invention. Inadequate mechanical stxength ch~racteristics, such as can occur when using mixed waste, can be compensated by a suitable selection of the $upporting layers.
The mats according to the invention are produced on the basis of the prior art. The central layer is applied to the lower supporting layer which serves as the conveyor belt.
The upper supporting layer is then supplied from a reel and the assembly formed by the supp~rting layers and the central layer is passed between the pairS of rollers used for prestreng-thening and said layers are joined together. The perforations can be obtained by pairs of rollers provided with corresponding needles, wh~ch in each case pass through a supporting layer and partly penetrate the central layer.
X!
Claims (14)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A fibre mat for producing three-dimensionally moulded mouldings, by means of the dry process, comprising a prestrengthened layer containing cellulose or lignocellulose fibres and deformable supporting layers with which the fibrous layer is joined, characterized in that the fibrous layer is arranged as the central later between two supporting layers and that the supporting layers comprise creped low-extension or ex-tension-proof foil materials joined to the central layer sur-faces, whilst maintaining the pulling out properties of the creping.
2. A fibre mat according to claim 1, characterized in that the creping comprises juxtaposed parallel folds.
3. A fibre mat according to claim 1, characterized in that the creping comprises cross-folds.
4. A fibre mat according to claim 1, 2 or 3, characterized in that the depth of the crepings is matched to the length of the fibres of the central layer in such a way that after pulling out the creping, the fibre assembly of the central layer is not interrupted, so that the shape and intensity of creping is adapted to the covering length of the fibres.
5. A fibre mat according to claim 1, 2 or 3, chara-cterized in that the surfaces of the crepe supporting layers facing the central later are joined to the latter by gluing or adhesion.
6. A fibre mat according to claim 1, characterized in that the supporting layers are joined together in puncti-form or linear manner at preferably equal intervals by ad-hesion or sewing through the central layer.
7. A fibre mat according to claim 6, characterized in that the punctiform or linear connections can be dissolved in heat.
8. A fibre mat according to claim 1, 2 or 3, characterized in that the creped supporting layers are provided with perforations.
9. A fibre mat according to claim 1, characterized in that the central layer has a high proportion of short fibres constituted by waste materials and is creped in the same way as the supporting layers.
10. A fibre mat according to claim 9, characterized in that the central layer comprises at least one sheet of paper or cardboard recovered from paper waste and impregnated with thermoplastic or duroplastic binders.
11. A fibre mat according to claim 9, characterized in that the central layer comprises at least one sheet of creped woven or non-woven fabric impregnated with thermoplastic or duroplastic binders.
12. A fibre mat according to claim 9, characterized in that the central layer comprises a thermoplastic material filled with cellulose or lignocellulose.
13. A fibre mat according to claim 9, 10 or 11, characterized in that the central layer comprises a plurality of layers interconnected by adhesion or sewing.
14. A fibre mat according to claim 1, 2 or 3, wherein said low extension or extension proof materials are selected from the group consisting of paper, plastic, metal and fabric.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP2945977.6 | 1979-11-12 | ||
| DE2945977A DE2945977C2 (en) | 1979-11-12 | 1979-11-12 | Manufacture of molded parts from layered fiber mats and fiber fleece |
| DE19792946969 DE2946969A1 (en) | 1979-11-19 | 1979-11-19 | Mat for dry-pressed esp. cellulosic article prodn. - contg. dense pre-strengthened central layer having low moisture content |
| DEP2946969.0 | 1979-11-19 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1164779A true CA1164779A (en) | 1984-04-03 |
Family
ID=25781990
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000363727A Expired CA1164779A (en) | 1979-11-12 | 1980-10-31 | Fibre mat for producing a three-dimensionally moulded moulding by the dry process |
Country Status (9)
| Country | Link |
|---|---|
| AT (1) | AT379106B (en) |
| BR (1) | BR8007345A (en) |
| CA (1) | CA1164779A (en) |
| ES (1) | ES488731A1 (en) |
| FR (1) | FR2469498A1 (en) |
| GB (1) | GB2063155B (en) |
| IT (1) | IT1126949B (en) |
| NL (1) | NL8005799A (en) |
| SE (1) | SE451691B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4655861A (en) * | 1983-11-28 | 1987-04-07 | Kiss G H | Process for producing moldings with deformable decorative surface |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2195952A (en) * | 1986-09-04 | 1988-04-20 | Structural Polymer Systems Lim | Composite sheet material |
| FR2728650A1 (en) * | 1994-12-23 | 1996-06-28 | Chomarat & Cie | Complex structure used for repair of conduits |
| CZ331695A3 (en) * | 1994-12-23 | 1996-07-17 | Chomarat & Cie | Composite textile material for repair and manufacture of pipelines |
| US20010046587A1 (en) * | 1998-12-21 | 2001-11-29 | Raj S. Michael | Encapsulated self adhering acoustic mat for sandwich used in vehicle interior systems |
| WO2013181379A1 (en) * | 2012-05-30 | 2013-12-05 | Interfacial Solutions Ip, Llc | Polymeric composites, resulting panels, and method for producing the same |
| IT201900019799A1 (en) | 2019-10-25 | 2021-04-25 | Imal Srl | PROCEDURE AND PLANT FOR THE REALIZATION OF PANELS IN WOODY MATERIAL |
Family Cites Families (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB482809A (en) * | 1936-12-11 | 1938-04-05 | Oscar Gossler Glasgespinst Fab | Improvements in and relating to heat and sound insulating bodies of spun glass |
| US2313345A (en) * | 1939-12-14 | 1943-03-09 | Wood Conversion Co | Thermal insulation |
| BE477352A (en) * | 1946-04-04 | |||
| DE1195066B (en) * | 1962-07-06 | 1965-06-16 | Hans Helmut Pfaffenholz Dipl I | Elastic element |
| US3484330A (en) * | 1966-04-28 | 1969-12-16 | Kimberly Clark Co | Disposable fabric |
| US3597299A (en) * | 1968-07-03 | 1971-08-03 | Kimberly Clark Co | Disposable washcloth |
| AU5894873A (en) * | 1972-08-14 | 1975-02-06 | Jojo Kimberly Kabushiki Kaisha | Disposable towel |
| US3953638A (en) * | 1973-11-26 | 1976-04-27 | The Procter & Gamble Company | Multi-ply absorbent wiping product having relatively inextensible center ply bonded to highly extensible outer plies |
| US3958055A (en) * | 1974-08-14 | 1976-05-18 | Kimberly-Clark Corporation | Adhesive bonding of isotropic fiber webs to form pattern bonded composites |
-
1980
- 1980-02-19 IT IT47944/80A patent/IT1126949B/en active
- 1980-02-19 ES ES488731A patent/ES488731A1/en not_active Expired
- 1980-10-13 AT AT0509080A patent/AT379106B/en not_active IP Right Cessation
- 1980-10-14 SE SE8007189A patent/SE451691B/en not_active IP Right Cessation
- 1980-10-21 GB GB8033890A patent/GB2063155B/en not_active Expired
- 1980-10-21 NL NL8005799A patent/NL8005799A/en not_active Application Discontinuation
- 1980-10-31 CA CA000363727A patent/CA1164779A/en not_active Expired
- 1980-11-06 FR FR8023717A patent/FR2469498A1/en not_active Withdrawn
- 1980-11-11 BR BR8007345A patent/BR8007345A/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4655861A (en) * | 1983-11-28 | 1987-04-07 | Kiss G H | Process for producing moldings with deformable decorative surface |
Also Published As
| Publication number | Publication date |
|---|---|
| SE8007189L (en) | 1981-05-13 |
| NL8005799A (en) | 1981-06-01 |
| GB2063155B (en) | 1984-01-11 |
| ATA509080A (en) | 1985-04-15 |
| ES488731A1 (en) | 1980-09-16 |
| AT379106B (en) | 1985-11-25 |
| IT8047944A0 (en) | 1980-02-19 |
| SE451691B (en) | 1987-10-26 |
| IT1126949B (en) | 1986-05-21 |
| GB2063155A (en) | 1981-06-03 |
| FR2469498A1 (en) | 1981-05-22 |
| BR8007345A (en) | 1981-05-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |