JPH04189535A - Method of manufacturing thermoplastic sandwich material product - Google Patents

Abstract

PURPOSE: To fold thermoplastic sandwiching materials to a certain angle by forming a certain angle at normals of two surfaces of the materials, forming the materials of a thermoplastic foam core and a top layer of a thermoplastic synthetic material, and reinforcing the top layer by a woven fabric, knitted cloth, web or unidirectionally aligned fiber group. CONSTITUTION: The method for manufacturing a thermoplastic sandwiching material product comprises a step of softening part of one side surface of the material over a distance corresponding to a length of a folding line of an angle formed by the two surfaces by using a die to form a pressing mark of the die on part of the top layer, and a step of folding the two surfaces of the material so that the softened surfaces are disposed at an inside of the angle.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD The present invention is an article made of thermoplastic sanderutsch material, at least two surfaces of which are angled, the sanderutrich material comprising a foam core of thermoplastic foam and a thermoplastic synthetic material. The present invention relates to a method for producing a top layer reinforced with a woven fabric, knitted fabric, web, or unidirectional fibers.

BACKGROUND OF THE INVENTION Sheet materials such as sandwich structures are widely used in various fields that require materials that are lightweight and have strength or rigidity. For example, it is used in airplanes, spacecraft, transportation facilities such as shipping, automobiles, etc.

Sand German timber generally consists of a lightweight core material and a top layer applied over the core material, which is usually reinforced. Appropriate rigidity can be obtained by properly adhering the top layer and core material. Other properties of this material are determined by the type of material used.

Known sandwich structures are based on a honeycomb structured core material. Another type of sand german wood is described in European Patent Application Nos. 264.495 and 268.148. The materials are all thermoplastic, consisting of a core material containing thermoplastic foam and two top layers of fiber-reinforced synthetic material, such as polycarbonate or polyetherimide.

European Patent No. 88202345.0 describes a thermoplastic flame retardant sheet material.

When such materials are used in products such as interior parts of airplanes, helicopters, etc., it is advantageous if the materials can be deformed by heating. The above-mentioned European Patent Application No. 268.148 describes a method in which a thermoplastic sheet material consisting of a foam core and a reinforcing top layer can be subjected to two- or three-dimensional deformation without losing any mechanical properties. However, there is also a need for a method of folding such sheet material at an angle while preserving its mechanical properties and without the need for composite removal operations.

Problems to be Solved by the Invention Therefore, there is a need for a method that can fold thermoplastic sandwich material at a certain angle with simple operations, and it is an object of the invention to meet this problem.

Means for Solving the Problems According to the present invention, the above-mentioned object of the invention corresponds to the length of the fold line of the angle formed by at least two surfaces by using a die to fold a part of one side of a thermoplastic sandwich material. softening over a distance so that the die impression is at least partially applied to the top layer; and folding the two surfaces of the thermoplastic material so that the softened surface is inside said angle. , the normals of at least two surfaces of the thermoplastic Santoy Sochi material are at an angle to each other, the Santoy Sochi material comprising a core of thermoplastic foam and a top layer of thermoplastic synthetic material, and the Santoy Sochi material having a top layer of This can be achieved by manufacturing products reinforced with woven or knitted fabrics, webs or groups of unidirectionally twisted fibers.

The method of the invention results in an unfoldable product in which the excess material of the top layer on the inside of the corners melts into the core foam. Heating causes this material to fuse with the core. The result is a folded product with the same strength as the original material.

With the normal folding method, the excess material will bulge up, making it impossible to obtain a proper fold. Further, in the method of the present invention, during folding, the top layer is bonded to each other due to the back pressure and hinging action of the foam. Although this is not the only reason, it is evident from the fact that the top layer is thus firmly fixed at the fold angle, resulting in form strength or tear strength in that area.

The sheet material f4 (sandwich structure) to be folded preferably comprises a thermoplastic foam-like core material, a woven fabric,
consisting of a thermoplastic composite reinforced with a knitted fabric, web or unidirectional fibers2
It consists of two top layers. Such sheet materials are detailed in the aforementioned European patent applications.

The raw materials from which the sheet material is made are also described in the European patent application. Specifically, the thermoplastic foam-like core material is polyetherimide foam, polycarbonate foam, polymethacrylamide foam, polyether sulfone foam, polyether ketone foam, polyether ether ketone foam, or polyphenylene sulfide foam.

The top layer preferably consists of a fiber-reinforced synthetic material, in particular a woven fabric, a knitted fabric, a web or a thermoplastic synthetic material reinforced with unidirectionally applied fibers.

The thermoplastic synthetic material that is the matrix of the top layer generally has a high softening point, such as polycarbonate, polyetherimide, polyamide, polysulfone, polyethersulfone, polyetherketone, polyetheretherketone or polyphenylene sulfide.

The thermoplastic foam-like core material is preferably polyetherimide foam, polycarbonate foam, polymethacrylamide foam, polyethersulfone foam, polyetherketone foam, polyether ether ketone foam, polyether ketone getone foam, polyphenylene sulfide foam. , or foams based on mixtures of these synthetic materials.

Optionally, fibers can be added into this foam material. Such fibers include glass fibers, polyamide fibers such as alumamide fibers, polyethylene fibers,
Selected from the group consisting of polyester fiber and carbon fiber.

The use of such a foam material in combination with the top layer and the thermoplastic synthetic materials described below for reinforcement results in an optimum reinforcement structure and maximum strength overall and at the points of reinforcement.

The following thermoplastic synthetic materials are preferably used: polyetherimides, polycarbonates, acrylate polymers, styrene polymers, polyethersulfones, polyetherketones, polyetherethergetones, polyetherketones and ketones, polyphenyleoxides, polyphenylene sulfides and A mixture of two or more of these synthetic substances.

In the top layer these synthetic materials are preferably reinforced with glass fibers, polyamide fibers such as alumamide fibers, polyethylene fibers, polyester fibers and carbon fibers.

The sandwich to be used is preferably heated and pressed to adhere each layer.

Surprisingly, the method according to the invention has the advantage that, by pre-treatment of the sheet material, structures with completely predictable angles can be obtained with the same strength as the base material. The softening on one side results in a kind of programming of the folds, thus resulting in predictable and reproducible fold angles. For thin materials, it is sufficient to use a die with a rounded bottom or a partially oval cross section, or a die with a certain angle.

If thick materials are used, this is insufficient as too much material must be melted away.

In that case a die with at least two angular cross sections is preferred.

The magnitude of the angle will depend on the nature of the folded structure and the material to be used. Relatively acute angles are advantageous because they provide good reproducibility. Therefore, the angle can be varied over a very wide range of approximately 15° to 175°.

When carrying out the method of the invention, the circumference of the die, i.e. the portion pushed into the top layer of the Sanderutsch material, is substantially φT.
(φ is the radian angle formed by the normals of the two surfaces, and T is the thickness of the Sanderutsch material). In this case, an optimal bending structure can be obtained without undue deformation of the sandwich material.

When using a tie having two or more corners in its cross section, the lateral surface of the tie is preferably conical to facilitate release of the die from the sandwich timber. There are at least two surfaces on the underside of the die that make angles with each other and with the lateral surfaces.

In the method according to the invention, at least a portion of one surface of the sand German timber is softened. This is usually done by heating. It is preferred to use a hot die so that softening occurs quickly. Of course, other methods are possible, but they are less preferred. It is also possible to combine surface heating with softening using a solvent or softening agent for the matrix of the top layer.

Preferred for this purpose is dichloromethane.

It is also possible to combine the softening of a portion of the top layer of the sand German timber with the heating of the entire sheet or a large part thereof.

In particular, it is preferable to heat the sandwich material subsequently locally or on the corresponding outside of the corner to be formed. For this purpose, the sandwich material must therefore be heated on the side opposite the die.

Such heating is not necessary unless it is sufficient to soften the material. You can heat it on the same side as the tie, but there is no particular advantage to doing so. In general, care must be taken in the degree of heating so that softening does not occur in areas other than those to be softened. Otherwise there is a risk of loss of fold/corner reproducibility.

As previously mentioned, softening of the surface is accomplished by heating the surface in combination with the optional use of a softening agent. The temperature used is that at which the matrix material of the top layer softens. However, the heating temperature and time must be selected such that a large excess of the foam core does not melt. The temperature to be selected will therefore depend on the materials used and will be determined by routine experimentation.

The thickness of the sandwich wood influences the shape of the die.

This thickness can be varied over a wide range, but in practice it is approximately 2.5
mm is the lower limit and the upper limit is l0C11, preferably 2.5C
It is I11.

Generally, during softening and when a die is pressed against the sand german timber, a tensile force is generated on the fiber by the pressing of the die, so that it has already been deformed to some extent and has begun to bend. Simultaneously or after heating, the two surfaces of the Sanderutsch wood are bent toward each other to form an angular structure. This can be done by hand, but with a suitable folding bench or brace! It is preferable to carry out.

Hereinafter, the present invention will be described by way of examples with reference to the drawings.

In the attached FIG. 1, die (a) is the simplest embodiment, and die (b) has a conical side surface and is suitable for use with sand german materials where peeling is a problem. Die (c)
is suitable for simple thin materials, while (d) and (e) are suitable for thicker materials where folding is more difficult and more material is present at the fold. Die (f) is suitable for use with extremely thin materials that are easy to process.

Figure 2 shows the die being pushed into the softened part of the Sanderutsch wood.
The two sides are then folded together to form an angle. As can be seen, the folds of the sander beam are preprogrammed by the angle of the die, thus resulting in a structure with precisely defined corners.

EXAMPLE Santoy of 10X 10CQI consisting of a 101 thick core of polyetherimide and two top layers of polyetherimide reinforced with glass fibers/child panels attached and 320° in the die of Figure 1(d). locally heated to C. The three angles are 175° and the circumference of the tie indentation is 18.
It was 2 mm. Push the die into the panel with a force of 0.750kg/Cl1f, then fold the two sides to
A 110° angle was created using the force of kg/CM panel width.

The panel was cooled and tested by applying a force to separate the two sides at a tensile strength of 25 kg. Although this corner structure was strong, it eventually failed. The strength of the panels in the folded areas was the same as the original strength of the sand German timber, which was ideal.

[Brief explanation of the drawing]

Fig. 1 of the accompanying drawings is a side view of various ties used in the method of the present invention, and Fig. 2 is a cross-sectional view showing the state in which a die is pushed into the sanderutchi material and the state in which the sanderutchi material is folded. Procedural amendment (method) September 6, 1991

Claims (14)

[Claims] (1) The normals of at least two surfaces of the thermoplastic sandwich material form an angle with each other, and the sandwich material consists of a core of thermoplastic foam and a top layer group of thermoplastic synthetic material, and the top layer group is made of woven or knitted material. Products reinforced with cloth, webs, or unidirectional fibers are made by cutting a portion of one surface of the thermoplastic sandwich material with a die to the length of an angular fold line formed by at least two surfaces. softening over a corresponding distance so that the die impression is at least partially applied to the top layer, and folding the two surfaces of the thermoplastic material so that the softened side is inside the angle. A manufacturing method consisting of steps. 2. A method as claimed in claim 1, characterized in that at least one, preferably two angles are formed in the die cross section. 3. The method of claim 1 or 2, wherein the circumference of the die is equal to or substantially equal to φΥ, φ is the radian angle made by the two surfaces, and Υ is the thickness of the sandwich material. . (4) Sandwich material is polyetherimide foam,
Claim 1 comprising a core of polycarbonate foam, polymethacrylamide foam, polyethersulfone foam, polyetherketone foam, polyetheretherketone foam, polyetherketone, ketone foam, polyphenylene sulfide foam or mixture foam of these synthetic materials. ~The method described in any of paragraphs 3. (5) The top layer is made of glass fiber, polyamide fiber such as alumamide fiber, polyethylene fiber,
polyester fiber, carbon fiber woven fabric,
5. A method according to any one of claims 1 to 4, wherein the material is reinforced with a knitted fabric, web or unidirectional fibers. (6) The method of claim 5, wherein the top layer is reinforced with fabric. 7. The method of claim 6, wherein the fiber length of the fabric substantially corresponds to the length of the sandwich material. (8) The method according to any one of claims 1 to 7, wherein the thermoplastic foam-like core also comprises fibers. (9) The method according to claim 8, wherein the fiber is any one of glass fiber, polyamide fiber, such as alumamide fiber, polyethylene fiber, polyester fiber, and carbon fiber. (10) The method according to any one of claims 1 to 9, wherein the foam core also contains a liquid crystalline substance. (11) The thermoplastic synthetic material of the top layer is polyetherimide, polycarbonate, acrylate polymer, styrene polymer, polyether sulfone, polyether ketone, polyether ether ketone, polyether ketone ketone, polyphenylene oxide, polyphenylene sulfide, and these. 11. The method according to any one of claims 1 to 10, wherein the synthetic material is selected from the group consisting of mixtures of two or more types of synthetic materials. (12) A method according to any one of claims 1 to 10, wherein the die has a conical side surface and at least two surfaces at the bottom making an angle with each other and with the side surface. (13) (a) contacting the top layer of the sandwich material with a die maintained at a temperature sufficient to soften the product surface; (b) softening at least a portion of the surface of the thermoplastic sandwich material with the contact; (c) the length of the softened portion is at least equivalent to the length of the angular fold line creating the angular structure in which die impressions are made on at least a portion of the surface; fold along the edges to form an angular structure, with the softened portions on the inside of the corners, so that at least a portion of the excess top layer material enters the foam core at the softened portions due to the folds. a thermoplastic foam core and at least one layer applied onto at least a portion of the foam core;
1. A method of manufacturing a product comprising two thermoplastic top layers, the top layer comprising a surface reinforced with woven fabrics, knitted fabrics, webs or unidirectional fibers, and having an angle. (14) A product made from a thermoplastic sandwich material having at least two angled faces obtained by the method according to any one of claims 1 to 12.