CN111331949B

CN111331949B - Laying structure and preparation method thereof

Info

Publication number: CN111331949B
Application number: CN202010296734.4A
Authority: CN
Inventors: 涂勤书; 蔡军爽; 尚克明; 刘振帅; 陶桂东
Original assignee: CRRC Qingdao Sifang Co Ltd
Current assignee: CRRC Qingdao Sifang Co Ltd
Priority date: 2020-04-15
Filing date: 2020-04-15
Publication date: 2022-05-27
Anticipated expiration: 2040-04-15
Also published as: CN111331949A

Abstract

The invention relates to the technical field of composite materials, in particular to a layering structure and a preparation method thereof. The core body is arranged on the outer skin; the layer structure still includes the foaming glue layer, and the core has the sawtooth structure towards the surface construction of outer covering, is equipped with the space between sawtooth structure and the outer covering, and the foaming glue layer is filled in the space to can be full of the space after the foaming glue layer is heated the inflation. The core structure can solve the problem that the structural stability of the core structure is adversely affected due to the debonding of the skin and the core in the existing core structure.

Description

Laying structure and preparation method thereof

Technical Field

The invention relates to the technical field of composite materials, in particular to a layering structure and a preparation method thereof.

Background

Sandwich structure materials, also called sandwich structure materials, are composite sandwich structures. The overall stress principle of the sandwich structure material is similar to that of an I-beam. The face plates of the sandwich structure material bear normal stress and shear stress in the face caused by bending moment, and the core body mainly bears transverse shear stress transmitted by the face plates, and meanwhile, the sandwich structure material also has the functions of stabilizing the two face plates and preventing local yielding. The composite sandwich structure has excellent specific rigidity and specific strength, namely, the weight is lower under the same rigidity and strength. In addition, the composite material sandwich structure also has the advantages of noise and vibration reduction, heat insulation, fatigue resistance, flame retardance, sound absorption, shock insulation and the like. The sandwich structure of the composite material can effectively reduce the unit volume cost of the material by reasonably selecting the core material and the panel. Therefore, the composite material sandwich structure has wide application in the industries of construction, aviation, rail transit and the like.

The sandwich structure of the composite material commonly used at present mainly comprises a honeycomb sandwich structure and a foam sandwich structure. In the existing foam sandwich structure, because the shrinkage rate of the foam core of the foam sandwich structure is different from that of the outer skin during molding, gaps are easily generated in the foam sandwich structure, and then the condition that the skin and the core are debonded can be caused in the sandwich structure, which can cause very adverse effects on the structural stability of the sandwich structure.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a layer laying structure to solve the problem that the structural stability of a sandwich structure is adversely affected due to the debonding of a skin and a core in the conventional sandwich structure.

The invention also provides a preparation method of the layering structure.

According to an embodiment of an aspect of the present invention, the lay-up structure includes an outer skin, a core body, and a foam layer, wherein the core body is disposed on the outer skin, a sawtooth structure is configured on a surface of the core body facing the outer skin, a space is disposed between the sawtooth structure and the outer skin, the foam layer is filled in the space, and the foam layer can fill the space after being heated and expanded.

According to one embodiment of the invention, the sawtooth structure comprises a plurality of convex parts, a plurality of convex parts are arranged on the surface of the core body facing the outer skin, grooves are formed between the adjacent convex parts, and the foaming glue layer is filled in the grooves and between the convex parts and the outer skin.

According to one embodiment of the invention, a first surface is formed on one end of each convex part facing the outer skin, a second surface is formed on one end of each concave part facing the outer skin, third surfaces are formed on two sides of each convex part respectively, and the third surfaces are connected between the adjacent first surfaces and the adjacent second surfaces; the first surface, the second surface and the third surface are all connected with the foaming glue layer.

According to an embodiment of the invention, said third surface is obliquely connected between adjacent said first and second surfaces.

According to an embodiment of the present invention, an inclination angle between the third surface and the adjacent first surface and second surface is 30 ° to 80 °.

According to one embodiment of the invention, the core is a foam core, and the material of the foam core is at least one of polyvinyl chloride, polymethacrylimide and polyethylene terephthalate.

According to one embodiment of the invention, the core further comprises a reinforcement skin connected to the outer skin, the core being connected between the reinforcement skin and the outer skin.

According to one embodiment of the invention, the core further comprises a curing glue layer, and the curing glue layers are respectively connected between the core body and the reinforcing skin and between the outer skin and the foaming glue layer.

According to another aspect of the invention, a method for preparing a ply structure comprises the following steps:

constructing a sawtooth structure on any surface of a core body, and paving a foaming adhesive layer on the surface of the core body constructed with the sawtooth structure;

taking the outer skin as a substrate, placing the core body on the outer skin, compacting the core body, and filling the foaming glue layer between the outer skin and the surface of the core body, which is provided with the sawtooth structure, so as to obtain a blank body;

and carrying out hot-press molding on the blank body so as to enable the foaming glue layer to expand and fill the space between the sawtooth structure and the outer skin.

According to one embodiment of the invention, the expansion factor of the foam layer is 5 to 7 times.

One or more technical solutions in the embodiments of the present invention have at least one of the following technical effects:

the paving structure comprises an outer skin and a core body, wherein the core body is arranged on the outer skin; the layer structure still includes the foaming glue layer, and the core has the sawtooth structure towards the surface construction of outer covering, is equipped with the space between sawtooth structure and the outer covering, and the foaming glue layer is filled in the space to can be full of the space after the foaming glue layer is heated the inflation. This core of spreading layer structure produces the shrink when being heated, in order to drive the foaming glue film of sawtooth structure shrink and extrusion space in, thereby utilize the sawtooth structure to be heated the shrink form and be heated the expanded foam glue film and produce the extrusion force, make the foam glue film produce more violent foaming inflation effect, and then make the foaming glue film after being heated the inflation can be full of the space completely, then the foam glue film in the space can be full of the clearance between core and the outer covering under the inflation state of being heated, can be full of the redundant space that the core produced because of being heated the shrink again, effectively promote the interlaminar bonding strength who spreads the layer structure.

Furthermore, the layer structure provided by the embodiment of the invention utilizes the sawtooth structure to generate acting force on the foaming adhesive layer in a heated state, so that pores with a certain range of sizes are formed in the foaming adhesive layer while the foaming adhesive layer is heated and expanded, resin permeation of the outer skin is facilitated, compactness of the layer structure can be improved, the outer skin is fused with the foaming adhesive layer during permeation, binding force among the outer skin, the foaming adhesive layer and the core body is further enhanced, and delamination of the layer structure is prevented.

Furthermore, the roller peeling strength of the layering structure can be improved by 20% -50%, and meanwhile, the shrinkage deformation of the layering structure caused by different thermal expansion coefficients of all layers can be further reduced, and the redundant gap generated by deformation is effectively eliminated; the appearance flatness and appearance can be increased, the surface quality problems of pinholes, glue shortage and the like of the appearance of the skin are effectively solved, and the product manufactured by adopting the layer spreading structure can be closer to the design size, so that the assembly precision of the product is improved.

The preparation method of the ply structure provided by the embodiment of the invention has all the advantages of the ply structure, and is not repeated herein.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic structural view of a ply structure according to an embodiment of the invention;

FIG. 2 is an enlarged view of a portion of the structure at A in FIG. 1;

FIG. 3 is a flow diagram of a method of making a ply structure according to an embodiment of the invention.

Reference numerals:

1: an outer skin; 2: a foamed glue layer; 3: a core body; 31: a convex portion; 32, a first step of removing the first layer; a first surface; 33: a second surface; 34: a third surface; 4: curing the adhesive layer; 5: the skin is reinforced.

Detailed Description

The embodiments of the present invention will be described in further detail with reference to the drawings and examples. The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience in describing the embodiments of the present invention and simplifying the description, but do not indicate or imply that the referred devices or elements must have a specific orientation, be constructed in a specific orientation, and be operated, and thus, should not be construed as limiting the embodiments of the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the embodiments of the present invention, it should be noted that, unless explicitly stated or limited otherwise, the terms "connected" and "connected" are to be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; may be directly connected or indirectly connected through an intermediate. Specific meanings of the above terms in the embodiments of the present invention can be understood in specific cases by those of ordinary skill in the art.

In embodiments of the invention, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "above," and "over" a second feature may be directly on or obliquely above the second feature, or simply mean that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of an embodiment of the invention. In this specification, the schematic representations of the terms used above are not necessarily intended to refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, various embodiments or examples and features of different embodiments or examples described in this specification can be combined and combined by one skilled in the art without contradiction.

As shown in fig. 1, the laminate structure according to the embodiment of the present invention includes an outer skin 1, a core 3, and a foam rubber layer 2. The core 3 is arranged on the outer skin 1, preferably the core 3 is compacted on the side of the outer skin 1 facing away from the design surface, so that the core 3 can be connected to the inside of the outer skin 1. The core 3 is towards the surface construction of outer covering 1 has the sawtooth structure, is equipped with the space between sawtooth structure and the outer covering 1, and foaming glue film 2 fills in the space to foaming glue film 2 can be full of the space after being heated the inflation.

The core 3 of this spreading layer structure produces the shrink when being heated to drive the shrink of sawtooth structure and extrude the foaming glue film 2 in the space, thereby utilize the sawtooth structure to produce the extrusion force to the foaming glue film that the shrink form is heated to expand. Sawtooth structure can make the foam adhesive layer produce more violent foaming inflation effect in extrusion process, and then makes the foam adhesive layer of thermal expansion fully fill up the space completely, and then the foam adhesive layer in the space can be full of the clearance between core 3 and the outer skin 1 under the thermal expansion state, can be full of core 3 because of the redundant space that the thermal contraction produced again, and the volume shrink that the effective compensation core 3 was heated and is produced to effectively promote the interlaminar bonding strength who spreads the layer structure.

It can be understood that the proper foaming multiplying power can enable the pores with proper sizes to be formed inside the foam rubber layer 2, so that the resin permeability is improved, the bonding force between the resin in the outer skin 1 and the foam rubber layer 2 is further enhanced, and the paving structure is more compact and firm.

Therefore, the compactness of the sandwich structure and the peeling strength of the bonding surface can be better increased and the delamination of the layering structure can be prevented by the sawtooth structure and the proper control of the foaming multiplying factor (namely the volume expansion multiplying factor) of the foaming rubber layer 2.

It should be noted that, in the layer structure described in this embodiment, the volume multiple of the thermal expansion of the foam adhesive layer 2 is controlled within a range from 5 times to 7 times, and the acting force of the sawtooth structure on the foam adhesive layer 2 in the heated state is combined, so that the pores within a certain range can be further formed in the foam adhesive layer 2 during the thermal expansion, which is beneficial for the resin of the outer skin 1 to permeate into the pores, and meanwhile, the compactness of the layer structure can be improved, and the outer skin 1 is fully fused with the foam adhesive layer 2 during permeation, so that the binding force among the outer skin 1, the foam adhesive layer 2 and the core body 3 is further enhanced, and delamination of the layer structure is prevented.

In one embodiment, as shown in fig. 2, the sawtooth structure includes a plurality of protrusions 31, the plurality of protrusions 31 are arranged on the surface of the core body 3 facing the outer skin 1, and grooves are configured between adjacent protrusions 31, and the foam rubber layer 2 is filled in the grooves and between the protrusions 31 and the outer skin 1. The sawtooth structure utilizes a plurality of convex part 31 and recess interval arrangement to at core 3 towards the surface texture zigzag's of outer covering 1 surface structure, in the thermoforming process, core 3 is heated the shrink and is driven adjacent convex part 31 and extrudees in to the recess, thereby produce violent squeezing action to the foaming adhesive layer 2 in the recess, make the foaming adhesive layer 2 of the rest in the foaming adhesive layer 2 linkage space in the recess produce more violent expanding action, thereby make foaming adhesive layer 2 more abundant fill up whole space.

In one embodiment, each protrusion 31 is configured with a first surface 32 toward one end of the outer skin 1, each groove is configured with a second surface 33 toward one end of the outer skin 1, each protrusion 31 is configured with a third surface 34 on both sides, the third surface 34 is connected between the adjacent first surface 32 and the second surface 33, so that the zigzag structure is configured on the surface of the core 3 by using a plurality of groups of the first surface 32, the second surface 33 and the third surface 34 arranged in a specific order, and the second surface 33 and the third surface 34 are connected with the foam layer 2, i.e., during the preparation of the green body of the laminate structure, the foam layer 2 is directly bonded on all of the first surface 32, the second surface 33 and the third surface 34, so that the foam layer 2 expands from the surface of the core 3 toward the outer skin 1 when expanded by heat, thereby causing the foam layer 2 in the groove to be preferentially squeezed during the heating, thereby achieving the purpose of promoting the expansion acceleration of the foaming rubber layer 2.

It will be appreciated that the third surface 34 is obliquely connected between the adjacent first and

second surfaces

32, 33. Preferably, the two third surfaces 34 on both sides of the same convex portion 31 are flared at the ends connected to the first surface 32, and correspondingly, the two third surfaces 34 are tapered at the ends connected to the second surface 33, so that the cross section of the convex portion 31 is configured as a regular trapezoid, as shown in fig. 2. This cross-sectional structure can make two adjacent convex parts 31 extrude in the recess of centre simultaneously when the shrink to can be better produce more better squeezing action to the foamed rubber layer 2 in the recess. It is further preferred that the third surface 34 is inclined at an angle of 30 ° to 80 ° to the adjacent first surface 32 and second surface 33, respectively.

In one embodiment, as shown in FIG. 1, the lay-up structure further includes a reinforced skin 5. The reinforcement skin 5 is attached to the outer skin 1, and the core 3 is attached between the reinforcement skin 5 and the outer skin 1. The surface of the outer skin 1, which faces away from the appearance surface, is an inner side surface, and the reinforcing skin 5 is used for reinforcing and inner supporting the structural strength of the inner side surface of the outer skin 1 and the surface of the core body 3. Preferably, the reinforcing skin 5 is wrapped on the core 3 except for the other surfaces provided with the saw-tooth structures, and the rest parts of the reinforcing skin 5 except the part wrapped with the core 3 are directly bonded on the inner side surface of the outer skin 1, so that the core 3 can be integrally fixed at the fixed position on the inner side of the outer skin 1, and the position deviation of the core 3 is prevented.

In one embodiment, as shown in FIG. 1, the lay-up structure further comprises a cured bondline 4. And curing glue layers 4 are respectively connected between the core body 3 and the reinforcing skin 5 and between the outer skin 1 and the foaming glue layer 2. The solidified glue layer 4 can replace the adhesive in the existing sandwich structure, and has the advantages of simple and convenient operation, firm bonding and uniformity.

It can be understood that the outer skin 1 and the reinforcement skin 5 described in the present embodiment are each composed of at least one of a resin-based carbon fiber reinforced composite material, a resin-based glass fiber reinforced composite material, and a resin-based aramid fiber reinforced composite material.

It will be appreciated that the cross-section of the core 3 is configured as a trapezoid as shown in fig. 1, but may also be configured in other common shapes, such as a rectangle, triangle or polygon, as long as it is sufficient that at least one face faces towards the outer skin 1. It is known that the cross-sectional shape of the regular trapezoid is the most preferable cross-sectional shape of the core 3, because the lower surface of the core 3 (i.e. the surface of the core 3 facing the outer skin 1) with the cross-section of the regular trapezoid has a surface with the largest area in geometric angle, so that the sawtooth structure with the largest area can be constructed on the surface, thereby further enhancing the bonding force between the core 3 and the outer skin 1.

It is understood that the core 3 is a foam core 3, and the material of the foam core 3 is at least one of polyvinyl chloride, polymethacrylimide and polyethylene terephthalate.

It will be appreciated that the individual dimensions of the sawtooth structure of the core 3 are adjustable. The sawtooth structure is formed by foaming through a die or processing through a special cutter.

It will be appreciated that the interlaminar bonding performance of the ply structure described in the examples of the present invention was verified by the drum peel test according to the sandwich structure drum peel strength test method provided in the standard No. GBT 1457-200. Through verification, compared with the existing sandwich structure, the roller peeling strength of the laying structure provided by the embodiment of the invention can be improved by 20% -50%. And, this structural setting of spreading layer structure can also further reduce the shrinkage deformation that the layer structure brought because of the thermal expansion coefficient difference of each layer, effectively eliminates the redundant clearance that warp and produce to can increase outward appearance plane degree and appearance, effectively solve surface quality problems such as pinhole, the scarce glue of covering outward appearance, make the product that adopts this layer structure to make can more be close to the design size, thereby promote the assembly precision of product.

Based on the paving structure provided by the embodiment of the invention, the embodiment of the invention also provides a preparation method of the paving structure. The preparation method of the ply structure has all the advantages of the ply structure and is not described again.

As shown in FIG. 3, the preparation method of the ply structure comprises the following steps:

s1, constructing a sawtooth structure on any surface of the core body 3, and fully paving a foam rubber layer 2 on the surface of the core body 3 constructed with the sawtooth structure;

s2, taking the outer skin 1 as a substrate, placing the core body 3 on the outer skin 1 and compacting, and filling the foaming glue layer 2 between the outer skin 1 and the surface of the core body 3 with the sawtooth structure to obtain a blank body;

and S3, performing hot-press molding on the blank body so that the foaming glue layer 2 is expanded and filled between the sawtooth structure and the outer skin 1.

In one embodiment, in step S2 of the method for preparing a ply structure according to the embodiment of the present invention shown in fig. 1, the method further includes:

s21, adhering or bonding the sheet-shaped foam adhesive layer 2 on all the first surface 32, the second surface 33 and the third surface 34 of the zigzag structure constructed on the core 3;

s22, taking the outer skin 1 as a base, placing the core body 3 on the outer skin 1, compacting, and filling the foaming glue layer 2 between the outer skin 1 and the surface of the core body 3 with the sawtooth structure, so as to obtain a blank.

In one embodiment, between step S21 and step S22 of the method for preparing a ply structure according to the embodiment of the present invention as shown in fig. 1, the method further includes:

s211, wrapping the sheet-shaped cured adhesive layer 4 outside the core body 3, and allowing the foam adhesive sheet to be located between all of the first surface 32, the second surface 33, and the third surface 34 of the sawtooth structure configured on the core body 3 and the cured adhesive layer 4.

In one embodiment, after step S22 of the method for preparing a ply structure according to the embodiment of the present invention shown in fig. 1, the method further includes:

s23, sequentially laying the sheets of prepreg of the reinforcing skin 5 on the surfaces of the core 3 except the surfaces on which the sawtooth structures are constructed, so that the central part of the reinforcing skin 5 is wrapped around the core 3, and the rest of the reinforcing skin 5 is bonded to the inner side surface of the outer skin 1.

According to the preparation method of the paving structure, the core body 3 can be firmly bonded with the outer skin 1 and the reinforcing skin 5 respectively. In subsequent step S3, autoclave molding is performed on the green body of the laminate structure, and the lower surface of the outer skin 1 shown in fig. 1 is an appearance surface. After the product is formed, the heated volume of the foaming adhesive layer 2 expands, the core body 3 contracts, the foaming adhesive layer 2 is utilized to fill the gap generated by the contraction of the foam core, and the gap is embedded with the sawtooth structure on the core body 3, so that the interlayer binding force of each layer of the layering structure is further enhanced.

The above embodiments are merely illustrative of the present invention and are not to be construed as limiting the invention. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that various combinations, modifications or equivalents may be made to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention, and the technical solution of the present invention is covered by the claims of the present invention.

Claims

1. A laying structure comprises an outer skin and a core body, wherein the core body is arranged on the outer skin, and the laying structure is characterized by further comprising a foaming glue layer, a sawtooth structure is constructed on the surface of the core body facing the outer skin, a space is arranged between the sawtooth structure and the outer skin, and the foaming glue layer is filled in the space; the sawtooth structure comprises a plurality of convex parts, the convex parts are arranged on the surface, facing the outer skin, of the core body, grooves are formed between the adjacent convex parts, and the foaming glue layers are filled in the grooves and between the convex parts and the outer skin;

the core body is heated to shrink to generate redundant gaps, and the space and the redundant gaps can be filled with the foaming adhesive layer after being heated to expand.

2. The ply structure of claim 1, wherein each of the protrusions is configured with a first surface at an end facing the outer skin, and a second surface at an end facing the outer skin, and wherein each of the recesses is configured with a third surface on each side, the third surfaces connecting between adjacent ones of the first and second surfaces; the first surface, the second surface and the third surface are all connected with the foaming glue layer.

3. The ply structure of claim 2, wherein the third surface is obliquely connected between adjacent first and second surfaces.

4. The ply structure of claim 3, wherein the angle of inclination between the third surface and the adjacent first and second surfaces is 30 ° to 80 °.

5. The ply structure of claim 1, wherein the core is a foam core of a material selected from at least one of polyvinyl chloride, polymethacrylimide, and polyethylene terephthalate.

6. The lay-up structure of any one of claims 1 to 5, further comprising a stiffening skin connected to the outer skin, the core being connected between the stiffening skin and the outer skin.

7. The ply structure of claim 6, further comprising a cured glue layer, the cured glue layer being connected between the core and the reinforcing skin and between the outer skin and the foamed glue layer, respectively.

8. A method of preparing a ply structure as claimed in any one of claims 1 to 7, comprising:

a sawtooth structure is constructed on any surface of the core body, the sawtooth structure comprises a plurality of convex parts, grooves are constructed between the adjacent convex parts, and foam rubber layers are fully paved in the grooves and on the surfaces of the convex parts;

taking the outer skin as a substrate, placing the core body on the outer skin, compacting the core body, and filling the foaming glue layer in the groove and between the convex part and the outer skin to obtain a blank body;

and carrying out hot-press molding on the blank body so as to enable the foaming adhesive layer to expand and fill the groove and the space between the convex part and the outer skin.

9. The method for preparing a foam layer according to claim 8, wherein the expansion ratio of the volume of the foam layer is 5 to 7 times.