JPH054907B2 - - Google Patents

Description

[Detailed description of the invention]

[Purpose of the invention] (Field of industrial application) The present invention provides scratch resistance, gloss, rigidity, adhesion to injected urethane foam, etc., as well as vacuum forming, pressure forming,
This invention relates to a three-layer sheet made of a new polypropylene resin with improved thermoformability such as press molding. (Prior art) Polypropylene resin sheets have excellent properties such as impact resistance, abrasion resistance, chemical resistance, heat resistance, creep resistance, and hinge resistance, and are relatively inexpensive, so they are used for home appliance parts, It is widely used in fields such as automobile parts, stationery/office supplies, and packaging materials. However, it still has many drawbacks in terms of adhesiveness, thermoformability such as vacuum forming, rigidity, and scratch resistance. Various proposals have been made in the past to improve these drawbacks, but none of them have yielded satisfactory results. For example, modified polyolefin resins have been proposed in which polyolefin resins are modified with unsaturated carboxylic acids such as maleic anhydride or acrylic acid to improve adhesion; Not only is it completely ineffective, but it also hardly improves the adhesion to the injected urethane foam. It is also known that polypropylene resin is blended with polyethylene or synthetic rubber to improve thermoformability for vacuum forming, etc., but polypropylene resins improved by this method generally have poor impact resistance and thermoformability. However, various properties such as scratch resistance, gloss, heat resistance, rigidity, and non-shrinkability deteriorate, and adhesion is not improved. Furthermore, a method of modifying polypropylene resin by adding fillers such as talc is known, but in this case, properties such as rigidity, heat resistance, and non-shrinkability are improved, but scratch resistance and Properties such as gloss, thermoformability, and impact resistance deteriorate, and adhesion is not improved. A common homopolymer of propylene and a product blended with a nucleating agent have relatively good scratch resistance and gloss, but even this is not sufficient, and this product has poor impact resistance, thermoformability, It has insufficient rigidity and no adhesive properties. As described above, it is not possible to obtain a sheet having various properties using conventionally known polypropylene resins and compositions thereof, either singly or laminated. (Problems to be Solved by the Invention) The present invention solves the problem of scratch resistance, gloss, rigidity, adhesion with injection foamed urethane, etc., and thermoforming such as vacuum forming without impairing the features of conventional polypropylene resin sheets. An object of the present invention is to provide a polypropylene resin sheet with improved properties, which has hitherto been incompatible. [Structure of the Invention] (Means and effects for solving the problem) The present inventors have improved scratch resistance, rigidity, adhesion with injection foamed urethane, etc., thermoformability such as vacuum forming, non-shrinkage property, etc. As a result of extensive research into polypropylene resin sheets with improved properties, we created a sheet with a three-layer structure, using polypropylene resin with a high degree of crystallinity for the surface layer that requires scratch resistance, and The surface layer uses a polypropylene resin composition containing a styrene polymer and a filler.
Furthermore, the middle layer of the three layers uses a polypropylene resin composition that has a melt flow rate (hereinafter referred to as MFR) in a specific range and has a specific relationship between MFR and Q value, and is blended with a filler. The present inventors discovered that the various problems of the prior art could be solved by adopting a sheet configuration of this type, which led to the present invention. That is, 3 of the polypropylene resin of the present invention
The layer sheet has (1) crystallinity of 0.945 or higher and MFR of 0.1 to 10 g/
Layer A of polypropylene resin (hereinafter referred to as A) for 10 min.
layer), MFR is 0.1 to 3g/10min.
Layer B (hereinafter referred to as layer B) of a composition in which 10 to 70% by weight of a filler is blended into a polypropylene resin whose relationship between (x) and Q value (y) is y≧15x, and a styrene-based polypropylene resin. Layer C of a composition containing 10-40% by weight of polymer and 5-40% by weight of filler
A three-layer sheet of polypropylene resin, characterized in that three layers (hereinafter referred to as C layer) are laminated in the order of A, B, and C. (2) The thickness of layer A is 30% or less of the total thickness, the total thickness of B is 50% or more of the layer thickness, and the thickness of layer C is 20% of the total thickness.
% or less, the three-layer sheet of polypropylene resin according to item (1) above. Since the various properties of the polypropylene resin sheet are improved, the practicality is extremely high. The resins and their compositions constituting the present invention are as follows. The polypropylene resin used for each ABC layer is
Homopolymers of propylene, copolymers of propylene with one or more α-olefins such as ethylene, butene-1, 4-methylpentene-1, hexene-1, octene-1, acrylic acid, maleic anhydride, etc. These are copolymers in which unsaturated carboxylic acids are graft-polymerized, and mixtures thereof. A propylene homopolymer is used for the layer requiring scratch resistance, and a copolymer with α-olefin or a graft copolymer of this and an unsaturated carboxylic acid is used in other layers from the viewpoint of impact resistance etc. is preferred. The crystallinity of the polypropylene resin used for layer A
Those with a value of 0.945 or higher are selected. Regarding the present invention, crystallinity is measured by infrared analysis or the like. The specific measurement method for infrared analysis is to take the sample as a specimen with a preferred thickness (for example, 40μ), take the infrared absorption spectrum of this specimen, and calculate the ratio of the absorbance of the spectrum at wave numbers 977 cm ^-1 and 997 cm ^-1 . (997cm
^-1 /977cm ^-1 ). The higher the crystallinity value, the better the scratch resistance and glossiness. However, the crystallinity of commercially available polypropylene resins is about 0.80 to 0.935, and even resin sheets with a maximum value of about 0.935 for commercially available products,
For example, scratching the edge of a 100 yen coin will easily cause noticeable scratches. If the resin sheet is easily scratched in this way, the commercial value of the resin sheet and its molded product will be significantly reduced due to the occurrence of scratches. The MFR of the polypropylene resin used for the A layer is
0.1~10g/10min, preferably 0.3~5g/
Selected from 10min. If it is less than 0.1, the fluidity will be poor, making it difficult to extrude into a sheet using an extruder, etc., and the gloss will decrease. If it exceeds 10, the fluidity will be too good, making it difficult to form a sheet with a uniform thickness, and the thermoformability will also deteriorate. If the polypropylene resin for the A layer falls within the limited range of the B layer resin, that is, if the MFR (x) and Q value (y) are in a relationship of y≧15x, the thickness should be limited. At least the thermoformability of the sheet is relatively good. However, from the viewpoint of rigidity, non-shrinkability, etc., the practical upper limit is 40 to 50% of the total thickness. MFR(x) in A layer
When using a polypropylene resin whose Q value (y) is y<15x, the thickness must be 30% or less of the total thickness. If the thickness ratio is increased more than this, thermoformability and the like will deteriorate and practicality will be lost. The polypropylene resin used in layer A of the present invention can be obtained, for example, by the method described in JP-A-58-104907. That is, the organoaluminum compound () or the reaction product () of the organoaluminum compound () and the electron donor (A) is reacted with titanium tetrachloride (C), and the solid product () obtained is further electron-donated. A solid product () obtained by reacting a body with an electron acceptor (B) is combined with an organoaluminum compound () and an aromatic carboxylic acid ester () to form a mixture of the aromatic carboxylic acid ester and the solid product (). Molar ratio/=0.2~
It can be obtained by polymerizing propylene or propylene and one or more α-olefins in the presence of a catalyst with a concentration of 10.0%. Also, crystallinity is 0.945 or more, MFR is 0.1-10
A polypropylene resin having a relationship between MFR (x) and Q value (y) in g/min as expressed by the formula y≧15x can be obtained by the method described in JP-A-58-219207, that is, by using an organoaluminum compound () or A solid product () obtained by reacting a reaction product () of an organoaluminum compound () and an electron donor (A) with titanium tetrachloride (C) is further added with an electron donor and an electron acceptor (B). The solid product () obtained by reacting with is combined with an organoaluminum compound () and an aromatic carboxylic acid ester (), and the molar ratio of the aromatic carboxylic acid ester and the solid product () is /
Propylene is polymerized in multiple stages in the presence of a catalyst with a ratio of 0.1 to 10.0, and in the first stage, 35 to 65% by weight of the total polymerization amount is polymerized, and in the second and subsequent stages, 65 to 35% by weight is polymerized. , the limiting viscosity of the middle-high molecular weight part of each polymer part produced in the first stage and the second stage and subsequent stages is [η] _H.If the limiting viscosity of the lower one is [η] _L , then 3.0≦[η] _H −[η] _L ≦6.5 can be obtained by adjusting the intrinsic viscosity of each polymer portion. In addition, the copolymer of propylene and one or more α-olefins is prepared by polymerizing propylene in the first stage in the presence of the catalyst described above, and then polymerizing propylene in the second and subsequent stages. It can be obtained by copolymerizing propylene and α-olefin, or by copolymerizing propylene and α-olefin from the first stage. In addition, copolymers in which unsaturated carboxylic acids such as acrylic acid and maleic anhydride are graft-polymerized can be obtained by graft-polymerizing the propylene homopolymer or copolymer obtained by the above method using a known method. You can get it. At this time, the grafting rate of the unsaturated carboxylic acid is not limited, but is 0.5 to 2.0.
The amount is preferably about % by weight, and when a copolymer with a high grafting rate is used, it is preferable to mix the copolymer with the raw material resin before grof polymerization and use it. The MFR of the polypropylene resin used for layer B and the intermediate layer of the three-layer sheet is 0.1 to 3 g/10 min, preferably 0.3 to 1 g/10 min. Also, a material with a specific MFR and Q value is used for this layer. MFR
If it is less than 0.1, the fluidity will be poor and it will be difficult to obtain a uniform sheet, and if it exceeds 3, the thermoformability will be greatly reduced due to the influence of other laminated layers, and thermoforming such as vacuum forming will not be possible. become unable. The Q value is a characteristic value indicating the molecular weight distribution of the resin, and specifically, it is the ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the resin. Q value and
Although MFR is an unrelated characteristic value, the present inventors have found that polypropylene resins in which the Q value (y) and MFR (x) have a relationship of y≧15x, preferably y≧20x, have thermoformability. It was found that this was significantly improved and was adopted as the composition of the three-layer sheet and B layer of the present invention. The Q value of commonly commercially available polypropylene resins is
It is about 4 to 7 regardless of MFR. The polypropylene resin in the limited range for layer B can be used in other layers as long as the limiting conditions for the resin in each layer are met. The thickness of the B layer is 50% of the total thickness when the limited range of polypropylene resin for the B layer is used only for the B layer.
% or more, in this case, the A layer is less than 30%, and the C layer is less than 30%.
The layer is less than 20%. If layer B is thinner than this, thermoformability, rigidity, and non-shrinkage properties are significantly reduced. When a resin limited to layer B is used for both layers A and B, the thickness of layer A can be up to about 50% of the layer thickness. The polypropylene resin used in the B layer of the present invention is produced by polymerizing propylene or propylene and α-olefin in multiple stages using a catalyst and a molecular weight regulator consisting of, for example, a titanium trichloride composition and an organoaluminum compound. It can be obtained by a method of polymerization by varying the amount of the molecular weight regulator. The present inventors have already proposed a composition for improving adhesion with injection foamed urethane, etc., but in the present invention, a styrene polymer and a filler are blended with polypropylene resin as an adhesion imparting layer on one side of the sheet. Adhesion is made possible by using this composition. The polypropylene resin used for the C layer, that is, the adhesive layer, can be any ordinary polypropylene resin and there is no need to use a material with a specific MFR, but from the viewpoint of extrudability for forming a sheet, etc. It is preferable to choose one that is close. The thickness of this layer is the total thickness
Less than 20%. If it is thicker than this, the impact resistance strength etc. will be greatly reduced, which is not preferable. Since this layer only needs to be provided with adhesive properties, it is practically 20 to 100μ.
It is sufficient if the layers are uniformly laminated with a certain thickness. Further, the adhesion of this layer can be further improved if the surface of this layer is treated by a generally known surface oxidation prevention method such as corona treatment, flame treatment, plasma treatment, etc. after forming the sheet. The styrenic polymers used for the C layer include polystyrene, acrylonitrile-butadiene-styrene copolymer (ABS resin), acrylonitrile-styrene copolymer (AS resin), styrene-methyl methacrylate copolymer, and rubber compounded polystyrene (HIPS resin). ), styrene-maleic anhydride copolymers, and mixtures thereof are preferred. The blending amount is 10-40
% by weight, preferably 15-35% by weight. If the amount is less than 10% by weight, the effect of improving adhesion and non-shrinkage is small, and if it exceeds 40% by weight, the impact resistance etc. will be greatly reduced and it will become brittle. The fluidity of the styrene polymer used is not particularly limited, but it is preferably close to the fluidity of the base polypropylene resin. The fillers added to the B or C layer include commonly used inorganic fillers such as talc, calcium carbonate, barium sulfate, calcium silicate, calcium sulfate, aluminum hydroxide, mica, and wood flour, rice hull powder, and cellulose short fibers. , short fibers of synthetic fibers, short fibers of carbon fibers, etc., and these can be used alone or in combination. The amount of filler added to layer B is 10 to 70% by weight, preferably 20 to 50% by weight. If it is less than 10% by weight, the effect of improving rigidity, non-shrinkage, heat resistance, etc. will be small;
If it exceeds 70% by weight, thermoformability, impact resistance, and extrusion processability into sheets will be significantly reduced. Further, the amount added to the C layer is 5 to 40% by weight, preferably 10 to 35% by weight. If it is less than 5% by weight, synergy with the styrene polymer will be small in terms of adhesion and non-shrinkage, and if it exceeds 40% by weight, impact resistance etc. will decrease and it will become brittle. The shape of the filler is approximately 50μ in particle size for inorganic systems, preferably
It is preferably less than 20 μm, and for powdered organic systems such as wood flour, it is preferably less than that which can pass through a 60-mesh sieve. In addition, from the viewpoint of handling, it is preferable that the fibrous filler has a fiber length of about 5 mm or less. Of the synthetic fibers, those having a melting point or decomposition point lower than the melting point of the polylopylene resin cannot be used in the present invention. The polypropylene resin and its composition used in the ABC layer of the present invention may include stabilizers, colorants, lubricants, nucleating agents, gloss improvers, antistatic agents, ultraviolet absorbers, flame retardants, and coupling agents. agent,
Rosin and its derivatives, petroleum resin, synthetic rubber, polyethylene, etc. can be used as appropriate. (Example) Test methods and materials used in Examples of the present invention are as follows. ●MFR: JISK6758 ●Crystallinity: Infrared analysis method ●Q value: GPC method ●Surface hardness: JISK5401 ●Glossiness: ASTMD523 ●Young's modulus: ASTMD882 ●Impact strength: ASTMD781 ●Thermoformability: The sheet is heated using a far-infrared heater 220℃
After heating in a controlled oven for 30 seconds, the opening is 300 mm long, the width is 200 mm, and the bottom is long.
A box-shaped molded product was created using a vacuum forming method using a box-shaped mold with a width of 280 mm, a width of 180 mm, and a depth of 100 mm, and the mold temperature was set at 30°C. This molded product was examined for thickness unevenness, wrinkles, and surface roughness to determine its quality. ●Shrinkage rate: The length and aroma of the opening of the molded product obtained in the thermoforming test were measured, and the dimensions of the molded product relative to the mold dimensions were investigated. ((Dimensions of molded product/dimensions of mold) x 100%) Adhesion: The inside of the box molded by the above thermoformability test is uniformly coated with a propane burner for about 0.3 seconds so that the C layer is on the inside of the box. flame treated,
Place this in an oven kept at 40℃ and warm it up. In this box, a mixture of 92 parts of polyether polyol (DRN1049) manufactured by Mitsui Nisso Urethane Co., Ltd. and 100 parts of isocyanate (MR200, containing Freon 11) manufactured by Nippon Polyurethane Industries Co., Ltd. was mixed with a mixer. Injected and foamed. After completion of foaming, the molded product was left in a room for about 1 hour, and then the degree of adhesion between the molded product and the foamed urethane was examined by peeling it off by hand, and the results were ranked as follows. ◎The molded product and urethane foam are completely adhered. ○Although it is adhered, there are some areas where the adhesion is insufficient. △Adhesion is weak and partially adhered. ×Not glued. ●Sheet creation: Extruder diameter is 65m/mφ, 50
Using a coextrusion device with three T dies (m/mφ, 40m/mφ) and a width of 800mm, the temperature of the extruder was set at 230°C, and three types of raw materials were extruded from separate extruders. A laminated sheet made of 3 layers in a T-die was set at 30℃ with a diameter of 350m/mφ.
A sheet with a thickness of 1.0 mm was created by extruding it between metal rolls of books and cooling and solidifying it. ●Materials used: The materials shown in Table 1 were used. As a stabilizer for 100 parts by weight of each material combination listed in the table.
Added 0.15 parts by weight of BHT and 0.15 parts by weight of calcium stearate, and added 0.2 PHR of paratertiary butylbenzoic acid as a nucleating agent to A and A'.
This was then pelletized and used.

【table】

[Table] Examples 1 to 10, Comparative Examples 1 to 13 Three-layer sheets shown in Table 2 were prepared using the polypropylene resins and their compositions shown in Table 1, and their performance was investigated. From Tables 1 and 2, sheets that meet the conditions of the present invention have hardness, gloss, thermoformability, adhesiveness,
It can be seen that while both Young's modulus (rigidity) and shrinkage rate are good, the comparative examples that do not satisfy the conditions of the present invention have some defects in terms of characteristics.

【table】

[Table] Examples 12 to 17, Comparative Examples 14 to 17 Using the polypropylene resins and their compositions shown in Table 1, sheets with different thicknesses of each layer were created.
We investigated its characteristics. The results are shown in Table-3.

〔Effect of the invention〕

As described above, the three-layer sheet of the present invention has excellent hardness, i.e., scratch resistance, gloss, thermoformability, adhesiveness, Young's modulus, i.e., rigidity, and non-shrinkage properties, and is used in automobile interior parts and home appliance parts such as refrigerators. , office supplies, equipment parts, and other molded products in various fields.

Claims (1)

[Scope of Claims] 1 Layer A (hereinafter referred to as layer A) of polypropylene resin having a crystallinity of 0.945 or more and a melt flow rate of 0.1 to 10 g/10 min;
Melt flow rate (x) and Q at 0.1~3g/10min
Layer B of a composition in which 10 to 70% by weight of a filler is blended with a polypropylene resin whose value (y) satisfies y≧15x.
(hereinafter referred to as B layer), and polypropylene resin containing 10 to 40% by weight of styrene polymer and 5 to 5% of filler.
Layer C of the composition containing 40% by weight (hereinafter referred to as layer C)
A three-layer sheet of polypropylene resin, characterized in that three layers are laminated in the order of ABC. 2. The three-layer sheet of polypropylene resin according to claim 1, wherein the thickness of the A layer is 30% or less of the total thickness, and the thickness of the C layer is 20% or less of the total thickness.