DE10312819B4 - Covering layer for engine compartment lining and method for its production - Google Patents

Abstract

Cover layer for engine compartment lining consisting of at least one binder-bound nonwoven fabric layer, wherein the nonwoven fabric layer of a mixture of
a) at least one of the fibers viscose (VC), polyester (PES), cellulose, polyamide (PA), polyolefin, preoxidized polyacrylonitrile (PAN) fibers and
b) hot melt adhesive fibers,
characterized in that the nonwoven fabric layer is solidified with a binder which has a thermoplastic behavior in the temperature range of 20 to 200 ° C and a thermosetting behavior above 200 ° C.

Description

The The invention relates to a cover layer for engine compartment lining, consisting at least one binder-bound nonwoven fabric layer, wherein the nonwoven layer of a mixture of a) at least one fibers viscose (VC), polyester (PES), cellulose, polyamide (PA), Polyolefin, preoxidized polyacrylonitrile (PAN) fibers and b) hot melt adhesive fibers consists. Furthermore, the invention relates to a process for the preparation such a cover layer.

Engine compartment linings serve the acoustic isolation of the engine noise.

Out the document WO 02/053373 multilayer materials are known which are used as engine compartment liners. There will be a Substrate layer by impregnation or coating a fabric or nonwoven fabric of inorganic Fibers or a paper made with a resin compound, as an inorganic filler Contains loess, where the resin is a thermosetting one Resin selected from the group consisting of phenolic resins, modified phenolic resins, modified phenol-urea resins, melamine resins and modified melamine resins, and a backside layer of aluminum or a galvanized steel plate.

Out JP 2002/004164 is a flame-retardant, resin-bonded nonwoven fabric known in which the nonwoven fabric with an emulsion of resin and a phosphorus-based flame retardant is impregnated. The nonwoven fabric is intended to be made of flame-retardant viscose fibers produced in a mixed spinning process and flame retardant Fibers of partially carbonized normal viscose and / or polyacrylonitrile fibers consist.

Farther is from document JP 02/070428 a cover layer for a hot melt forming known in which a styrene resin on the surface of a polyester fibers and carbon fibers of existing nonwoven fabric and copolymerized in a hot pressing process is formed.

The document DE 197 26 965 C1 discloses a special Dämmaterial, which is used for sound insulation in all areas of vehicles, and which is constructed in the manner of a mass-spring system. The spring element of the mass-spring system comprises a nonwoven fabric containing polyester bicomponent binder fibers and at least one type of crimped polyester fibers. For this purpose, a heavy layer in the form of a film or a coating with a soft, partially elastic spring layer is connected. The spring element preferably has a basis weight in the range of 600 to 1000 g / m ² . A binder which is additionally optionally applied to the nonwoven fabric and which is familiar to a person skilled in the art is generally provided, for example, for improving the abrasion resistance.

When Engine compartment lining are predominantly mats made of phenol resin-impregnated tear-cotton used with a black colored nonwoven fabric on the later visible Page covered. The nonwoven fabric must be liquid-repellent next to the cover of the tear cotton against various liquids such as water, gasoline, diesel, brake fluid, engine oil and in places Flame retardant equipped be. The connection with the tear cotton is made by hot melt adhesive fibers causes. Preference is given to bicomponent fibers of polyolefins and / or Polyester on the back of the nonwoven fabric are produced. The composite is added 200-230 ° C in heated Pressing over 60-120s deformed.

used are binder-bound and needled nonwovens, which are usually in a second process step through an impregnation process flame retardant and liquid repellent equipped be and back in one step be coated by powdering or printing with the adhesive medium.

Out cost reasons As a rule, binder-bonded nonwovens are preferred, however when deforming into deeper shapes often tear and then through the needle-punched nonwovens to increased Costs must be replaced.

The Automotive industry calls for a covering layer material for the engine compartment lining, which has a very high three-dimensional thermal formability above from 200 ° C shows. Furthermore, the material should have flame retardant as well as liquid repellent properties equipped his and a big one thermal bondability against the sub-material, which usually consists of cheap wool exhibit. It should have the equipment without an additional Process step done.

The Invention has set itself the task of a cover for engine compartment lining with a binder-bonded nonwoven fabric, wherein the Material meets the requirements of the automotive industry, too like needled nonwovens for deeper deformations is appropriate, the integration of a flame retardant and liquid-repellent equipment is allowed, and the cover layer is inexpensive.

According to the invention Task solved by a cover layer consisting of at least one binder-bound Nonwoven fabric layer, wherein the nonwoven fabric layer of a mixture of a) at least one of viscose (VC), polyester (PES), Cellulose, polyamide (PA), polyolefin and / or preoxidized polyacrylonitrile (PAN) fibers and b) melt adhesive fibers, and wherein the nonwoven fabric layer with solidified to a binder which is a thermoplastic Behavior in the temperature range of 20 to 200 ° C and a thermosetting behavior above 200 ° C having. This behavior is due to the crosslinking hardening of the Binder achieved.

advantageously, becomes the nonwoven fabric with a condensing crosslinking binder bound, which at a temperature up to 200 ° C only precrosslinked and at a Temperature over Cures 200 ° C. The binder is selected from the group of acrylic acid co-polymers and terpolymers with styrene, butadiene and / or acrylonitrile, preferably from the group of acrylic acid co-polymers and terpolymers with styrene.

The Binder may further flame retardant, hydrophobing and / or Oleophobing agents included. Preferably, as a flame retardant a halogen and heavy metal free nitrogen-containing phosphorus compound available. Preference is given to a phosphonic acid derivative having an elemental content of ≥ 10% by weight Nitrogen and ≥ 5 Wt .-% phosphorus, which shows a high synergism. It will no hygroscopic behavior of the flame retardant and no softening effect detected on the binder. The nonwoven layer itself consists from a mixture of a) at least one of the viscose (VC) fibers, Polyester (PES), Cellulose, polyamide (PA), polyolefin and / or preoxidized polyacrylonitrile (PAN) fibers and b) hot melt adhesive fibers of polyolefin or polyester bicomponent fibers.

The covering layer according to the invention has a weight per unit area of 20 to 200 g / m ² , the weight ratio of the fibers used per square meter of the fibers used per square meter being in the range from 0.5: 1 to 2: 0.5.

The Invention has also set itself the task of a production technology simple and inexpensive Method for producing a cover layer with a binder-bound Specify nonwoven fabric, the material meets the requirements of the automotive industry enough and also like needle fleeces for deeper deformations is suitable. In addition, at the same time the integration a flame retardant and liquid repellent equipment possible be.

In the process according to the invention, staple fibers having a length of 20 to 200 mm and a fiber titer of 0.8 to 40 dtex are laid to form a batt with a basis weight of 10 to 200 g / m ² and impregnated with a binder which dissolves the object has a thermoplastic behavior in the temperature range of 20 to 200 ° C and a thermosetting behavior above 200 ° C. The binder is preferably applied in foam form.

The Flooring is advantageously carried out so that the ratio of elasticity transverse to the machine direction (cross direction CD) to the machine direction (machine direction MD) is in the range of 1: 4 to 2: 1.

The Nonwoven fabric layer has a content of bicomponent fibers in the Fiber mixture on, as a hot melt adhesive of permanent anchorage to the underlying zip-cotton mat serve. The proportion of bicomponent fibers on the nonwoven layer is preferably at least 5.0% by weight. The bicomponent fibers exist while a polymer having a melting range of 240 ° C to 265 ° C as the core and a polymer having a melting range of 120 ° C to 170 ° C as a shell.

One Advantage of the method according to the invention for making a cover layer for engine compartment liners in the simplified design of the production process, taking Staple fibers of white or spun-dyed black fibers through a carding process in a disordered Way be filed.

there For example, the pile obtained may be strongly oriented in the machine direction. Subsequently the impregnation takes place with a binder mixture in the form of a foam containing the pile penetrated and for a complete Wetting of the batt and thus ensures the binder absorption.

Essential is the selection of the binder, this being two different ones Has phases of plastic behavior. First, a thermoplastic Behavior in the range of room temperature to 200 ° C, in particular 195 ° C, and second, a phase characterized by a thermoset behavior above 200 ° C through the complete curing of the binder is achieved.

Further additions the binding system are flame retardants, fluororesins and optionally Pigments around the cover layer a flame retardant and liquid repellent properties as well as a uniform black coloring to rent.

Of the Drying process is carried out at a temperature below 200 ° C. According to this Process conditions, a nonwoven fabric is obtained, which is a thermoplastic Character and has a thermal bonding ability. The hotmelt adhesive, for example, a polyolefin or polyester bicomponent fiber allows the bonding of the cover material after the thermal shaping at Temperatures greater than 200 ° C against the Shoddy material.

For reaching The three - dimensionally stable formability is in contrast to the previously used cover materials no preference in the orientation of the Non-woven fabric flors required before joining with the tear wool material.

While conventional binder-bound nonwoven fabric for the cover layer of engine compartment liners always had to be used transversely to the machine direction, is this is no longer necessary.

The with the cover layer according to the invention manufactured engine compartment liners show a very good three-dimensional Moldability above 200 ° C. There is no delamination of the molded parts. Own the parts a very good thermal dimensional stability and show no shrinkage. The cover layer has a highly effective flame retardant before and after thermal shaping at temperatures above 200 ° C and a permanently hydrophobic and oliophobic character. By the proposed manufacturing process the costs decrease, because of a separate finishing step with flame retardants and liquid repellents can be dispensed with and also on the additional operation of a Coating with a hot glue can be waived.

The The invention is explained in more detail below with reference to three examples:

example 1

From white and black spun-dyed polyester fibers of low strength and a fiber denier of 3.3 dtex and a fiber length of 60 mm, a batt with a basis weight of 17 g / m ^{2 is} transversely placed. A second batt a basis weight of 5 g / m ² dtex from polyolefin or polyester bicomponent hotmelt adhesive fibers having a fiber denier of 3.3 and a fiber length of 60 mm placed transversely to the first, wherein by increasing the speed takes place a re-orientation of the fibers and the machine direction (CD / MD) elastic ratio is about 2.0: 1.

The batt is impregnated with a binder foam of an acrylic acid co- or terpolymer with styrene, butadiene and / or acrylonitrile, resulting in a solids content of about 18 g / m ² . The drying is done by hot air below 200 ° C, whereby the binder hardening is avoided.

The finished surface weight of the cover material is 40 g / m ² . The finished cover layer is used in a three-dimensional molding process at temperatures greater than 200 ° C against an existing example of shredded wool sub-material and connected by the contained hot melt adhesive fibers. The shaping takes place at a pressure of greater than 200 bar / cm ² for a period of 60 to 90 seconds.

The molded parts obtained with the covering layer according to the invention are perfectly coated with the covering layer and also adhere to the sharp bends of the part without cracks and delamination. The edges can be cut cleanly. The flame retardant and liquid repellent properties are obtained after the thermal molding process.

Example 2

From white or black spun-dyed polyester fibers having a low tenacity, a fiber denier of 3.3 dtex and a fiber length of 60 mm, a 20 g / m ² pile is produced in a transverse configuration. A second batt with a basis weight of 11 g / m 2 is made from a mixture of 50% by weight of white or black spun-dyed polyester fibers having a low strength, a fiber denier of 3.3 dtex and a fiber length of 60 mm and 50% by weight of a polyolefin or polyester-bicomponent melt-bonded fiber having a fiber denier of 3.3 dtex and a fiber length of 60 mm laid across the first, wherein by increasing the speed reorientation of the fibers takes place and the elasticity properties CD / MG are 2: 1.

The web is impregnated with a binder of a thermally crosslinking co- or terpolymer of styrene and / or butadiene and acrylic acid having a solids content of 49 g / m ² and dried with hot air below 200 ° C, so that a complete curing of the binder is avoided. The basis weight of the finished cover material is 75 g / m ² .

Example 3

From 60 wt .-% black spun-dyed polyester fibers with a fiber denier of 1.7 dtex and a fiber length of 40 mm and 40 wt .-% of a black pre-oxidized PAN fiber with a fiber titer of 2.4 dtex and a fiber length of 60 mm a pile of 48 g / m ² occupied. The pile laying takes place in a transverse configuration.

A second batt with a basis weight of 18 g / m ² is made from a mixture of 50% by weight of white or black spun-dyed polyester fibers having a low strength, a fiber denier of 1.7 dtex and a fiber length of 38 mm and 50% by weight of one Polyolefin or polyester bicomponent hot melt adhesive fiber with a fiber titer of 3.3 dtex and a fiber length of 60 mm laid across the first, with an increase of the speed, a reorientation of the fibers takes place and the elasticity ratio CD / MD 2: 1.

The batt is impregnated with a binder mixture having a solids content of 54 g / m ² . The drying takes place with hot air below 200 ° C so that the complete binder hardening is avoided. The basis weight of the finished cover material is 120 g / m2.

In Table 1 is the flame strengths and repellency in accordance with the standard DIN 75200 and DIN 53906 according to the examples 1 to 3 obtained cover layers assembled.

Tabelle 1

Table 1

Claims (12)

Covering for engine compartment lining consisting of at least one binder-bound nonwoven layer, the nonwoven fabric layer of a mixture of a) at least one of viscose (VC), polyester (PES), cellulose, polyamide (PA), polyolefin, preoxidized polyacrylonitrile (PAN ) -Fiber and b) melt adhesive fibers, characterized in that the nonwoven fabric layer is solidified with a binder which has a thermoplastic behavior in the temperature range of 20 to 200 ° C and a thermosetting behavior above 200 ° C. Covering layer according to claim 1, characterized that the nonwoven fabric layer with a condensing crosslinking Bonded binder which precrosslinked at a temperature up to 200 ° C. and at a temperature above 200 ° C is cured. Covering layer according to one of claims 1 or 2, characterized in that the binder is selected from the group of acrylic acid co-polymers and terpolymers with styrene, butadiene and / or acrylonitrile. Covering layer according to one of claims 1 to 3, characterized in that the binder flame retardant, hydrophobing and / or Oleophobierungsmittel contains. Covering layer according to one of claims 1 to 4, characterized in that the binder as a flame retardant halogen and heavy metal free Containing nitrogen-containing phosphorus compounds. Covering layer according to claim 5, characterized in that that as a flame retardant nitrogen-containing phosphonic acid derivatives are contained with an elemental content of nitrogen ≥ 10 wt .-% and phosphorus ≥ 5 Wt .-%. Covering layer according to one of claims 1 to 6, characterized in that it has a basis weight of 20 to 200 g / m2, with the weight ratio of per square meter used fibers to the per square meter of binder used in the range of 0.5 1 to 2: 0.5. Covering layer according to one of claims 1 to 7, characterized in that the nonwoven fabric layer is melt adhesive fibers of polyolefin or polyester bicomponent fibers. Method for producing a cover layer according to one of the claims 1 to 8, wherein the staple fibers having a length of 20 to 200 mm and a Fiber titer of 0.8 to 40 dtex to a batt with a basis weight from 20 to 200 g / m 2 and impregnated with a binder, which is a thermoplastic behavior in the temperature range of 20 to 200 ° C and has a thermoset behavior above 200 ° C. Method according to claim 9, characterized in that that the binder is applied in foam form. Method according to claim 9, characterized in that that the pile is made so that the ratio of elasticity across the Machine direction to the machine direction in the area from 1: 4 to 2: 1. Method according to one or more of claims 9 to 11, characterized in that the proportion of the fusion adhesive fibers at the nonwoven fabric layer is at least 5 wt .-%.