JP2019001030A - Flame-retardant laminate - Google Patents

Abstract

To provide a flame-retardant laminate which is lightweight and has high flame retardancy performance.SOLUTION: A flame-retardant laminate 1 has metal plates laminated on both surfaces of a core material 2 containing 25-40 wt.% of a polyolefin resin and 60-70 wt.% of a flame-retardant material, where the flame-retardant material is formed of magnesium hydroxide or an inorganic material containing magnesium hydroxide as a main component. The core material 2 is foamed by a foaming material, configured such that a diameter of a foamed part formed by foaming is 500 μm or less, a specific gravity of the core material 2 is 0.6 or more, and the total calorific value when a heat-buildup test is performed is 8 MJ/square meter or less.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a flame retardant laminate formed by laminating a metal plate on a core material made of a resin plate containing a resin and a metal hydroxide as a flame retardant.

  A canapé-like or sandwich-structured laminate formed by joining a metal plate to a resin plate mainly made of resin has extremely high strength and elasticity compared to a simple resin plate, but compared to a metal plate. It is lightweight and has excellent bending workability, and is generally used widely. In addition, a flame-retardant laminate having flame retardancy by adding a metal hydroxide or a flame retardant to the resin plate has been proposed.

  Conventionally, various flame retardants have been used to impart flame retardancy. Among them, the flame retardant itself or harmful substances contained in the flame retardant may become a problem during disposal, and metal hydroxides such as aluminum hydroxide and magnesium hydroxide are used as the flame retardant. . However, since the metal hydroxide has a higher specific gravity than a general resin, the flame retardant laminate becomes heavy, and it is difficult to carry and handle.

  In order to solve these problems, for example, in Patent Document 1, in a flame retardant composite plate in which an aluminum plate is bonded to both surfaces of a polyolefin-based resin sheet, the paint applied to the surface of the aluminum plate after a combustion test has a predetermined area. As described above, the flame retardancy is improved by peeling or whitening.

  In addition, in the present applicant, in the laminated body in which the metal plate is bonded to the resin plate via the adhesive, the flame retardancy is improved by including the metal hydroxide in the adhesive. A laminate is proposed.

JP 2007-125715 A Japanese Patent Laid-Open No. 2004-358772

  By the way, the flame-retardant performance composite plate described in Patent Document 1 is limited in the type of coating, the coating method and coating conditions, the coating film configuration, and the coating thickness because the coating applied to the aluminum surface is limited. There was a fear.

  On the other hand, in the flame retardant composite plate as described above, if the core material is foamed, the specific gravity of the core material is reduced and the weight is reduced. However, if the absolute amount of resin is reduced, the shape of the core material may not be maintained. is there.

  The present invention solves the above problems and provides a flame retardant laminate that is lightweight and has high flame retardancy.

  In order to solve the above-mentioned problems, the present inventors have intensively studied, and as a result, when the resin plate is made to be foamed with a foaming agent in order to reduce the weight, by maintaining the foamed state in a predetermined state, the weight is reduced. Thus, it was learned that a flame retardant laminate having high flame retardant performance can be obtained, and the present invention has been completed.

  That is, the flame retardant laminate according to the present invention includes a metal plate laminated on both surfaces of a core material including 25 to 40% by weight of a polyolefin-based resin and 60 to 70% by weight of a flame retardant. A flame retardant laminate, wherein the flame retardant is made of magnesium hydroxide or an inorganic material mainly composed of magnesium hydroxide, and the core material is foamed by a foam material, The formed foamed portion has a diameter of 500 μm or less, a specific gravity of the core material of 0.6 to 1.1, and a total calorific value when the exothermic test is performed is 8 MJ / square meter or less. It is what.

  More preferably, the core has a specific gravity of 0.7 to 1.1.

  According to the present invention, in the core material, while controlling the diameter of the hollow portion formed by the foam material and exceeding the predetermined specific gravity, the flame retardancy can be maintained and the weight can be reduced. Because it can, it will be excellent in transport efficiency and workability.

  By setting the specific gravity of the core material to 0.7 to 1.1, it becomes easier to express flame retardancy.

It is a perspective view which shows one Embodiment of the flame-retardant laminated body which concerns on this invention. It is an expansion detailed cross section in the AA cross section of FIG. It is a table | surface which shows the Example and comparative example of a flame-retardant laminated body which concern on this invention. FIG. 2 is a micrograph (drawing substitute photograph) of a part of a fractured portion in the core material created in Example 1. FIG. FIG. 3 is a micrograph (drawing substitute photograph) of a part of a fracture portion in the core material of the flame-retardant laminate obtained in Example 2. FIG. 2 is a micrograph (drawing substitute photograph) of a part of a fractured portion in the core material created in Comparative Example 1; FIG. 4 is a micrograph (drawing substitute photograph) of a part of a fracture portion in a core material prepared in Comparative Example 2. FIG. 6 is a micrograph (drawing substitute photograph) of a part of a fractured portion in the core material of the laminate obtained in Comparative Example 3.

  Embodiments of the present invention will be specifically described below with reference to the drawings. Note that the present invention is not limited to these embodiments. The present invention includes various modifications made by those skilled in the art without departing from the scope of the present invention.

  FIG. 1 is a cross-sectional view showing an embodiment of the flame-retardant laminate according to the present invention, and FIG. 2 is an enlarged detailed cross-sectional view taken along the line AA of FIG. The flame retardant laminate 1 has a structure in which metal plates 3 are laminated on the front and back of a plate-like core material 2, and the core material 2 is arranged between the metal plates 3 and 3. An adhesive layer 4 is provided for bonding the metal plate 3. The thickness of the flame retardant laminate 1 is preferably about 1 to 5 mm, the thickness of the core material 2 is preferably 0.5 to 4 mm, and the thickness of the metal plate 3 is preferably 0.1 to 1 mm.

  The core material 2 includes a flame retardant material and a polyolefin-based resin. The flame retardant is mainly composed of magnesium hydroxide. Specifically, pulverized natural ore composed mainly of magnesium hydroxide such as brucite, synthesized magnesium hydroxide from magnesium components contained in seawater, added magnesium salt to aqueous sodium hydroxide solution And the like using a colloid of precipitated magnesium hydroxide as a raw material. Among these, those derived from seawater can be suitably used because they have a relatively small impurity content and are easily uniform in particle size. The smaller the particle size of the flame retardant is, the more the unit surface area increases, so the flame retardant performance is effectively expressed. However, the smaller the particle size, the lower the dispersibility in the polyolefin resin, and the core There is a possibility that the formability of the material 2 may decrease. Accordingly, the average particle size of the flame retardant is preferably 1 to 10 μm.

  The polyolefin resin may be an α-olefin polymer such as ethylene, propylene, or butene, or may be a polymer obtained by polymerizing an α-olefin with ethylene. An acid or its ester, a copolymer of acrylic acid or its ester, a polyethylene terminal modified with maleic anhydride or the like may be used. Further, these resins may be used alone or in combination of two or more. In general, magnesium hydroxide contained in a flame retardant is said to start decomposing at 250 ° C., and a resin that can be molded at a temperature lower than that is preferable, and polyethylene or polyethylene-based material is preferably used. When a polyethylene resin is used, high density polyethylene, medium density polyethylene, low density polyethylene, and linear low density polyethylene may be used alone or in combination.

  Moreover, in the core material 2, in order to improve the dispersibility of a metal hydroxide, you may use a dispersing agent, it becomes easy to disperse | distribute a metal hydroxide uniformly in resin by a dispersing agent, and flame retardance performance. Can be improved. As the dispersant, for example, a saturated fatty acid metal salt such as zinc stearate can be used. Moreover, in order to improve the moldability and smoothness of the core material 2, a lubricant may be used, and an ester or amide of a saturated fatty acid is used.

  Examples of the foaming agent used for foaming the core material 2 include a chemical foaming agent that releases nitrogen gas, carbon dioxide gas, and the like by thermal decomposition and chemical reaction, and a material that expands by heat. Examples of the inorganic chemical foaming agent in the former chemical foaming agent include bicarbonates such as sodium carbonate and nitrites such as sodium nitrite. Organic chemical foaming agents include azo compounds and hydrazide compounds. More specifically, azo compounds such as 2,2′-azobisisobutyronitrile, azodicarbonamide, azohexahydrobenzonitrile, hydrazide compounds such as benzenesulfonyl hydrazide and diphenyl sulfone -3,3'-disulfonylhydrazide. Examples of the latter include thermally expandable microcapsules.

  The blending ratio of the flame retardant in the core material 2 is preferably 60% by weight or more. When the blending ratio of the flame retardant is less than 60% by weight, the flame retardancy is hardly stably exhibited. On the other hand, the blending ratio of the polyolefin resin is preferably 25% by weight or more. If the blending ratio of the polyolefin resin is less than 25% by weight, the moldability is lowered. The blending ratio of the polyolefin resin is more preferably 30% by weight or more.

Thermally expandable microcapsules are usually those in which a thermally expandable substance is enclosed in a shell. Shells include vinylidene chloride, acrylonitrile, copolymers of acrylonitrile and vinylidene chloride, copolymers of nitrile resins such as acrylonitrile and methacrylonitrile and methacrylate esters such as methyl methacrylate and ethyl methacrylate, and nitrile resins. And a copolymer of acrylic acid ester such as methyl acrylate and ethyl acrylate. As the thermally expandable substance, isobutane, normal butane, normal pentane, isopentane, petroleum ether-based low-boiling hydrocarbons are used. Moreover, the average particle diameter before foaming of a thermally expansible microcapsule is about 15-50 micrometers.
Commercially available products of thermally expandable microcapsules include “Matsumoto Microsphere” manufactured by Matsumoto Yushi Seiyaku Co., Ltd., “Microsphere” manufactured by Kureha Co., Ltd., “Expancel” manufactured by Nippon Philite Co., Ltd., “Sekisui Chemical Co., Ltd.” Advancel ”and the like.

  In the foaming agent, the heat-expandable microcapsules are preferable because the shape after expansion is easily maintained by making the softening temperature or melting temperature of the shell higher than that of the polyolefin resin contained in the core material 2. That is, the polyolefin resin is at or above the melting temperature, and the shell can easily form a state at the softening temperature or below the melting temperature. Therefore, even if pressure is applied to the core material 2 by bending the molten core material 2 or attaching the metal plate 3 to the molten core material 2, the shell body does not easily deform. And the fall of the expansion ratio of the core material 2 can be suppressed, without a thermally expansible microcapsule breaking. In addition, since it is difficult for bubbles to form each other between the shells, it is possible to suppress the occurrence of partial foaming or the outflow of foaming gas from the front and back surfaces and side surfaces of the core material 2.

  The core material 2 preferably has a closed cell structure. The closed cell structure means that a foaming agent for foaming the core material 2 is formed by using a thermally expandable microcapsule and an independent foaming portion is formed in the core material 2 or a chemical foaming agent is used. The foamed part foamed in the material 2 does not form much foam and has a closed cell-like form.

  The flame retardant laminate in which the metal plates 3 are laminated on both surfaces of the core material 2 can have predetermined performance in the exothermic test described later.

  The metal plate 3 is generally made of an aluminum alloy, stainless steel, iron, titanium, or the like. The metal plates 3 on the front and back sides of the core material 2 are usually the same, but different types of metal plates may be used on the front and back sides in consideration of the installation location and application.

  The adhesive layer 4 is for adhering the core material 2 and the metal plate 3, and may be formed by applying an adhesive such as urethane or epoxy during or after the core material 2 is molded. However, when polyethylene is used as the core material 2, the core material 2 is made of a modified resin that has been imparted with an adhesive force to the metal plate 3 based on a polyolefin resin or a resin highly compatible with the polyolefin resin. You may form by carrying out extrusion molding simultaneously at the time of shaping | molding.

  The exothermic test is a test method based on ISO5660-1, and the test body is made into a square shape of 99 mm ± 1 mm, and the test for irradiating the surface of the test body with radiant heat and operating the electric spark is performed for a certain period of time to measure the total heat generation amount Is. Regarding the total calorific value, the standards are stipulated in Article 2-9 of the Building Standards Act and Article 108-2 of the Law Enforcement Ordinance, and the exothermic test is conducted for 20 minutes, and the total calorific value is 8 MJ / square meter. If it does not exceed, one standard as a so-called nonflammable material can be satisfied.

  The core material 2 has a specific gravity of preferably 0.6 or more, more preferably 0.7 or more. When the specific gravity is less than 0.6, the volume of the foamed portion in the core material 2 becomes too large, the foamed portion breaks bubbles, or the foamed portions join each other, resulting in difficulty in the core material 2. There is a possibility that the distribution of the fuel material becomes dense and the flame retardancy of the flame retardant laminate 1 is lowered, or that the uneven flame retardance depending on the location is increased. Moreover, the moldability of the core material is likely to be lowered. By setting the specific gravity of the core material 2 to 0.7 or more, flame retardancy is more easily exhibited, and therefore, more preferable.

  On the other hand, the specific gravity of the core material 2 is preferably 1.1 or less. When the specific gravity exceeds 1.1, the content of the polyolefin resin constituting the core material 2 is relatively reduced, and it is difficult to uniformly disperse the heat-expandable microcapsules. Since the diameters also have a certain distribution, they combine to easily increase the amplitude of the specific gravity of the resin depending on the location of the core material 2. Furthermore, it is difficult to realize a light feeling.

  In order for the core material 2 to have a closed cell structure, the diameter of the foamed portion is preferably 500 μm or less. If the diameter of the foamed part exceeds 500 μm, the foamed part breaks up, or the foamed parts tend to form a large diameter, and the foamed part tends to collapse when the flame retardant laminate 1 is molded. The specific gravity is less likely to drop. Moreover, the location where there is much foaming locally and the location where few are conversely easily occur, there is a possibility that strength and flame retardancy are lowered, or surface properties such as the smoothness of the surface of the metal plate are deteriorated. In the foamed part, whether one foamed part has become larger or a plurality of foamed parts have been combined is not always clear by surface observation, and these are regarded as one foamed part without distinction. More preferably, the diameter of the foamed portion is 300 μm or less.

  Hereinafter, although the example and comparative example of the present invention are given and the composition and effect of the present invention are further explained, the present invention is not limited to these examples.

Example 1
65% by weight of magnesium hydroxide (Kinsei Matec Co., Ltd .: MagShield S, average particle size: 3-5 μm),
32% by weight of polyolefin resin (manufactured by Nippon Polyethylene Co., Ltd .: UR951 linear low density polyethylene, MFR = 3.5 (g / 10 min)),
As a lubricant, a mixture of 0.75% by weight of zinc stearate (manufactured by NOF Corporation: Zinc stearate G) and 2.25% by weight of ethylene bisstearamide (manufactured by Cognis Japan: LOXAMID) was kneaded. Granules were created.
Next, 2 parts by weight of thermally expandable microcapsules (manufactured by Sekisui Chemical Co., Ltd .: Advancel P403M1) as a foaming agent are mixed with 100 parts by weight of the granules as a basic blend, and a single screw extruder is mixed. Then, the core material 2 was prepared by extrusion molding into a sheet at a cylinder temperature of 140 to 160 ° C. and a T-die temperature of 140 ° C.
Using this core material 2, subsequently, a modified polyethylene resin sheet is disposed on both sides of the core material 2 as an adhesive layer, and an aluminum plate having a thickness of 0.2 mm is further disposed as a metal plate. A 4 mm laminate was created. In addition, since the compounding quantity of the flame retardant in the core material 2 reduces by addition of a foaming agent, the compounding quantity of the flame retardant contained in the core material 2 is also described in FIG.

(specific gravity)
The specific gravity of the core material 2 was measured using a specific gravity measuring device (Shinko Denshi Co., Ltd .: DME-220H) after removing the metal plate from the obtained laminate and taking out the core material 2. The measurement results are shown in FIG. In addition, in the below-mentioned comparative example which does not produce a laminated board, specific gravity of the obtained core material was measured.

(Formability of core material)
Since the obtained core material 2 has a relatively high blending ratio of the flame retardant, the smoothness of the surface may be deteriorated particularly during extrusion molding. On the other hand, the core material may contain a dispersant to enhance the dispersibility of the flame retardant, and may contain a lubricant to improve the smoothness of the surface, but the dispersant and lubricant are a combination of the core material 2 and the metal plate. When setting it as a laminated structure, there exists a possibility that adhesion | attachment may be inhibited when the core material 2 and a metal plate are adhere | attached using an adhesive agent like this form. In this embodiment, it is known that the blending of the dispersant and the lubricant does not inhibit the adhesion. In this embodiment, the smoothness of the laminated surface laminated with the metal plate during the extrusion molding of the core material 2 is visually observed. In FIG. 1, “◯” was given when no obvious irregularities were observed and the surface was almost smooth, and “X” was given when obvious irregularities were observed. The evaluation results of formability are shown in FIG.

(Foamed state of core material)
The obtained core material 2 or laminate is broken in the thickness direction in a direction in which a cross section as shown in FIG. 2 appears, and a microscope (a microscope manufactured by Hilox Co., Ltd., product number: KH-1300) is obtained. ) To observe the fracture surface. A micrograph of a part of the fractured portion of the core material 2 is shown in FIG. As a result of surface observation, a pair of fractured surfaces formed by fracture are observed, and when a foamed portion having a diameter (thickness direction of the core material 2, vertical direction in FIG. 4) exceeding 500 μm is not observed, When the evaluation was “◯” and a foamed part exceeding 500 μm was observed, the evaluation of the foamed state was “X”. The evaluation results of formability are shown in FIG.

(Flame retardant performance)
The exothermic test was performed as a test for evaluating the flame retardancy of the obtained laminate. Specifically, three 10 cm square samples were prepared from the obtained laminate, and all three had high flame retardancy if the total calorific value after 20 minutes of exothermic test did not exceed 8 MJ / square meter. Judgment is acceptable and the evaluation is “○”, and if there is even one sample whose total calorific value exceeds the standard, the flame retardant performance varies or the flame retardant performance is insufficient, and it is judged as rejected. The evaluation was “x”. The evaluation results of this flame retardant performance are shown in FIG.

(Bending strength test)
A part of the obtained laminate was cut out and subjected to a bending test based on JIS K7171 plastic-bending method. Five samples were prepared, and the average value of the measured values was taken as the bending strength. The bending strength by the bending strength test is shown in FIG.

(Example 2)
In Example 1, a laminate was obtained in the same manner as in Example 1 except that an aluminum plate having a thickness of 0.1 mm was used as the metal plate and the total thickness was 3 mm. As in Example 1, the measurement results of the specific gravity of the core material 2, the evaluation results of the moldability of the core material 2, the observation results of the foamed state of the core material 2, the evaluation results of the flame retardant performance, and the results of the bending strength test are shown. It is shown in 1. Moreover, the micrograph of a part of fracture | rupture part of the core material 2 in a laminated body is shown in FIG.

(Comparative Example 1)
In Example 1, a core material 2 was obtained in the same manner as in Example 1 except that 2 parts of an organic chemical foaming agent (manufactured by Sankyo Kasei Co., Ltd .: Cellmic) was mixed as the foaming agent. Similar to Example 1, measurement results of the specific gravity of the core material 2, evaluation results of moldability of the core material 2, and observation results of the foamed state of the core material 2 are shown. In addition, since the evaluation of the moldability of the core material 2 was “x”, it was determined that the moldability was poor and a laminate was not created. Therefore, the evaluation results of flame retardancy and the bending strength test were not performed. FIG. 6 shows a micrograph of a part of the fractured portion of the two-core material before the laminate is created.

(Comparative Example 2)
In Example 1, a core material 2 was obtained in the same manner as in Example 1 except that 2 parts of an inorganic chemical foaming agent (manufactured by Dainichi Seika Kogyo Co., Ltd .: Fine Cell Master) was mixed as the foaming agent. Similar to Example 1, measurement results of the specific gravity of the core material 2, evaluation results of moldability of the core material 2, and observation results of the foamed state of the core material 2 are shown. In addition, since the evaluation of the moldability of the core material 2 was “x”, it was determined that the moldability was poor and a laminate was not created. Therefore, the evaluation results of flame retardancy and the bending strength test were not performed. FIG. 7 shows a micrograph of a part of the broken portion of the core material 2 before the laminate is produced.

(Comparative Example 3)
In Example 1, a core material 2 was obtained in the same manner as in Example 1 except that 2 parts of an inorganic chemical foaming agent (manufactured by Dainichi Seika Kogyo Co., Ltd .: Fine Cell Master) was mixed as the foaming agent. The evaluation of the formability of the core material 2 was “x”, but for comparison, the same as in Example 1 except that the total thickness was 3 mm using an aluminum plate having a thickness of 0.1 mm as a metal plate. Thus, a flame retardant laminate was obtained. The measurement result of the specific gravity of the core material 2, the evaluation result of the moldability of the core material 2, the observation result of the foamed state of the core material 2, the evaluation result of the flame retardant performance, and the result of the bending strength test are shown in FIG. Moreover, the one part microscope picture of the fracture | rupture part of the core material 2 after laminated body preparation is shown in FIG.

  When Example 1 and Example 2 are compared, there is a difference in the specific gravity of the core material 2, but from the observation of the foamed state of the core material 2, in each case, a foamed portion of about 50 to 150 μm is observed, and the diameter No foaming part exceeding 300 μm was observed. Moreover, it turned out that it has high flame retardance performance from the evaluation result of flame retardance performance. On the other hand, when Example 2 and Comparative Examples 1 to 3 are compared, the specific gravity is about the same, but when FIGS. 5 to 8 are compared, the moldability and foaming state of the core material 2 are greatly different. In FIG. 8, a foamed part having a diameter exceeding 500 μm is observed, and as a core material composition, polyolefin resin is 25 to 40% by weight, and the decomposition type used in Comparative Examples 1 to 3 This foaming agent is considered to reduce the moldability of the core material 2.

  According to the flame-retardant laminate according to the present invention, it is possible to reduce the weight while maintaining high flame-retardant performance, so that it can be suitably used as an interior material, exterior material, and ceiling material of a building. .

1 Flame Retardant Laminate 2 Core Material 3 Metal Plate 4 Adhesive Layer

Claims (2)

A flame retardant laminate comprising a metal plate laminated on both surfaces of a core material comprising 25 to 40% by weight of a polyolefin-based resin and 60 to 70% by weight of a flame retardant,
The flame retardant is made of magnesium hydroxide or an inorganic material mainly composed of magnesium hydroxide,
The core material is foamed by a foam material, and the diameter of the foamed portion formed by the foaming is 500 μm or less,
The core has a specific gravity of 0.6 to 1.1,
A flame-retardant laminate having a total calorific value of 8 MJ / square meter or less when the exothermic test is conducted.   The flame retardant laminate according to claim 1, wherein the core material has a specific gravity of 0.7 to 1.1.