JP2000026679A - Thermoplastic resin sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain thermoplastic resin foamed sheets excellent in moldability, heat resistance, and oil resistance and additionally having tearability. SOLUTION: Thermoplastic resin foamed sheets can be obtained from resin compositions containing (A) 3-97 wt.% styrenic resin and (B) 97-3 olefinic resin, and component (A) and component (B) form a structure of their respective continuous phases and a so-called islands-in-sea structure, and with respect to the phase structure in the direction of thickness, the layer in the neighborhood of the center is of a so-called islands-in-sea structure and at least one surface layer is of a structure of their respective continuous phases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention has excellent heat resistance and oil resistance, is suitable as a food container material, and has an easy tearing property, so that it can contribute to weight reduction at the time of recovery. The present invention relates to a thermoplastic resin sheet and a thermoplastic resin foam sheet. Further, the present invention relates to a container made of the thermoplastic resin sheet or the thermoplastic resin foam sheet.

[0002]

2. Description of the Related Art Styrene resins are widely used as container materials for various foods such as side dishes because of their excellent moldability and rigidity. Since heat resistance and oil resistance are inferior, improvement of these properties is required.

[0003] Further, conventional styrene resin food containers have poor tearability, so that when they are collected for disposal or reuse as resources, it is difficult to reduce the weight by tearing the containers. Therefore, since it is lightweight but bulky, there is a problem that it takes time for handling such as transportation and a lot of space is required.

[0004] In order to solve such a problem, it is necessary to have not only an improvement in heat resistance and oil resistance but also an easy tearing property. Japanese Patent Application Laid-Open No. 7-292171 discloses a technique aimed at improving the tearing property of polystyrene / polypropylene = 61/39 to 98/2, and SEBS (styrene / ethylene / butadiene / styrene copolymer) as a compatibilizer. An easily tearable film made of a resin composition containing the resin composition is disclosed. However, in this easily tearable film, there is no disclosure about the relationship between the phase structure of the film and the easily tearable property.

[0005] The present invention has excellent heat resistance and oil resistance, and is easily tearable, so that it is easy to use at the time of use and has excellent handleability at the time of collecting as dust. It is an object to provide a resin sheet and a thermoplastic resin foam sheet. Another object of the present invention is to provide a container comprising the thermoplastic resin sheet and the thermoplastic resin foam sheet.

[0006]

Means for Solving the Problems As a result of repeated studies to achieve the above object, the present inventors have found that a styrene is obtained by changing a sheet structure into a coexistence system of a bicontinuous phase structure and a sea-island structure by constituent components. The present inventors have found that heat resistance and oil resistance can be improved and easy tearing properties can be imparted without impairing the moldability and rigidity of the base resin, and the present invention has been completed.

That is, the present invention relates to (A) a styrene resin
97% by weight and 97 to 3% by weight of (B) olefin resin
Which is a sheet obtained from a resin composition containing a thermoplastic resin sheet, wherein the component (A) and the component (B) in the sheet form a bicontinuous phase structure and a sea-island structure. . Further, the present invention is a foamed sheet obtained by foaming and molding the above resin composition, wherein in the foamed sheet, the component (A) and the component (B) form a bicontinuous phase structure and a sea-island structure. A thermoplastic resin foam sheet is provided. Further, the present invention provides a container made of a thermoplastic resin sheet or a thermoplastic resin foam sheet.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic resin sheet of the present invention
It is obtained by molding a resin composition containing a styrene resin as the component (A) and an olefin resin as the component (B).

Examples of the styrene resin (A) used in the resin composition include a polymer of a styrene monomer and a copolymer of a styrene monomer and another monomer copolymerizable therewith.

As the styrene monomer, styrene,
Alkyl-substituted styrene such as 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-ethylstyrene, 4-t-butylstyrene, 2,4-dimethylstyrene, α-methylstyrene, α-methyl-4- One or more selected from α-alkyl-substituted styrene such as methylstyrene, halogenated styrene such as 2-chlorostyrene and 4-chlorostyrene, and the like can be given.

Other monomers copolymerizable with the styrene monomer include acrylic acid or methacrylic acid, methyl acrylate or methyl methacrylate, ethyl acrylate or ethyl methacrylate, butyl acrylate or butyl methacrylate, acrylic acid 2 Acrylic acid such as -ethylhexyl or 2-ethylhexyl methacrylate (C _1-
C ₈₎ esters or methacrylic acid (C ₁ ~C ₈₎ esters, acrylonitrile, maleic anhydride, maleimide,
One or more types selected from maleic acid or derivatives thereof such as N-substituted maleimide such as N-methylmaleimide and N-ethylmaleimide can be mentioned.

The styrene resin as the component (A) may be a rubber-modified styrene resin. Examples of the rubber used in the production of the rubber-modified styrene resin include non-styrene rubbers such as butadiene rubber, butadiene-isoprene rubber, butadiene-acrylonitrile rubber, ethylene-propylene rubber, isoprene rubber, acrylic rubber, and ethylene-vinyl acetate rubber; At least one selected from styrene rubbers such as butadiene rubber and styrene-isoprene rubber can be used. The butadiene rubber may be a high cis type having a high content of cis-1,4 structure or a low cis type having a low content of cis-1,4 structure. When the rubber-modified styrenic resin is used, the content of the rubber component in the resin is 1 to 2
It is preferably 0% by weight.

The polymerization form when the component (A) is made into a copolymer is not particularly limited, but may be a block copolymer,
It may be a random copolymer or a copolymer having a tapered block structure.

The content of the component (A) in the resin composition is from 3 to 97% by weight, preferably from 10 to 90% by weight, particularly preferably from 30 to 80% by weight.

Examples of the olefin resin (B) used in the resin composition include homopolymers of olefin monomers such as ethylene, propylene and butylene, and other monomers copolymerizable with the olefin monomer and the olefin monomer. And copolymers thereof. Examples of the other monomer copolymerizable with the olefin monomer include the styrene monomer used in the component (A) and a monomer copolymerizable with the styrene monomer. As the component (B), polypropylene is preferable, and any of low density, medium density and high density polypropylene may be used.

The content of the component (B) in the resin composition is from 97 to 3% by weight, preferably from 90 to 10% by weight, particularly preferably from 70 to 20% by weight.

The resin composition may further contain one or more compatibilizers selected from the following (C-1) to (C-4) as component (C). When a component that also acts as a compatibilizing agent with the component (B) is used as the component (A), the compatibilizing can be sufficiently performed only by the action alone. There is no.

(C-1) A copolymer comprising a vinyl aromatic compound and a conjugated diene compound or a hydrogenated product thereof. Examples of the vinyl aromatic compound include monomers used in the component (A) described above, and examples of the conjugated diene compound include butadiene, chloroprene, and isoprene.

(C-2) An epoxidized copolymer of a vinyl aromatic compound and a conjugated diene compound or a hydrogenated product thereof. Examples of the copolymer comprising a vinyl aromatic compound and a conjugated diene compound include a copolymer (C-1).

(C-3) A copolymer of a styrene monomer as a constituent unit of the component (A) and a monomer as a constituent unit of the component (B).

(C-4) A copolymer of a vinyl aromatic compound and a compound having a carboxyl group or an acid anhydride. Examples of the vinyl aromatic compound include the styrene-based monomer used in the component (A) described above, and examples of the compound having a carboxyl group and the acid anhydride are copolymerizable with the styrene-based monomer used in the component (A). Other monomers can be mentioned.

The compounding amount of the compatibilizer of the component (C) is as follows:
And the total amount of component (B) is preferably 0.1 to
The amount is 20 parts by weight, particularly preferably 0.5 to 10 parts by weight.

If necessary, a colorant such as a pigment, a dispersant such as a higher fatty acid salt, an inorganic filler such as talc, a conductivity-imparting agent, an antistatic agent, and silicone are added to the resin composition. be able to.

In the thermoplastic resin sheet of the present invention, the component (A) and the component (B) form a bicontinuous structure and a sea-island structure. In the present invention, "bicontinuous phase structure"
MD direction (sheet flow direction) and TD direction (M
Direction perpendicular to the direction D),
The styrene-based resin phase of the component (A) and the olefin-based resin phase of the component (B) do not exist in an independent state such as particles or fibrous shapes, but both phases are connected to each other in a network. This means that a mixed phase structure is formed in the state. The “sea-island structure” refers to the M
In either of the D direction and the TD direction, one component forms an ocean (matrix phase) and the other component forms an island (disperse phase), or both components are independent of each other such as particles or fibrous. It means that it exists in a state.

In the thermoplastic resin sheet of the present invention, for example, as shown in FIG.
Preferably, the layer (T ₁ ) near the center of the thickness has a sea-island structure, and at least one surface layer (T ₂ ) has a bicontinuous phase structure. Further, in the thermoplastic resin sheet of the present invention, the thickness ratio T ₁ and one of T ₂ is preferably _{T 1 / T 2 = 1 /} 50~50 / 1, particularly preferably 1/20 ２０20/1.

FIG. 1 is used only for explaining the positional relationship between the bicontinuous phase structure and the sea-island structure in the thermoplastic resin sheet of the present invention, and the structure of FIG. The structure of the sheet is not limited. Further, the bicontinuous phase structure and the sea-island structure do not have a clear boundary in the thickness direction, and a portion that does not correspond to any phase structure may exist at the boundary between the two phase structures.

The thermoplastic resin sheet of the present invention is, for example,
After the resin composition pellets (resin pellets) are melted and kneaded by an ordinary extruder, a circular die, T
It can be obtained by extrusion molding through a die or the like. At this time, the bicontinuous phase structure and the sea-island structure coexist, for example,
In order to obtain a thermoplastic resin sheet having an arrangement relationship as shown in FIG. 1, the sheet is formed by the following method.

The resin pellets as raw materials are mixed at a predetermined compounding ratio, and charged into an extruder. Since the phase structure is affected by the mixing ratio and type of the resin, a sheet having a desired sea-island structure and a bicontinuous phase structure can be obtained by adjusting the melting temperature of the resin, the number of rotations of the screw, and the like. Also,
When using multiple extruders, use a separate extruder for the central layer and the surface layer, and obtain a sheet having the desired sea-island structure and bicontinuous phase structure by adjusting the type and blending ratio of the resin. Can be.

The thermoplastic resin sheet of the present invention can be made into a laminate of two or more layers by laminating resin non-foamed sheets made of the same or different materials on one or both sides. The resin non-foamed sheet used in this case can be appropriately selected from desired materials in accordance with the intended use and properties to be imparted, for example, heat resistance, abrasion resistance, improvement in surface appearance, printability, and the like. . As a method for producing a laminate, a co-extrusion method,
A known method such as a dry lamination method can be applied.

The foamed thermoplastic resin sheet of the present invention is obtained by subjecting the above resin composition to foam molding in accordance with the method for producing a thermoplastic resin sheet. The expansion ratio is preferably from 1.1 to 3.0 times, particularly preferably from 1.2 to 3.0 times.
2.0 times.

Examples of the foam molding method include a method of adding a chemical foaming agent and performing extrusion molding, a method of performing extrusion molding while injecting a foaming gas raw material, and a method of extruding a resin composition impregnated with a liquid foaming gas raw material. A molding method or the like can be applied. Examples of the chemical foaming agent and foam gas raw material include hydrocarbons such as sodium hydrogen carbonate, ammonium hydrogen carbonate, azodicarbonamide, azobisisobutyronitrile, liquid propane, and butane.

The thermoplastic resin foam sheet of the present invention has the same phase structure as the thermoplastic resin sheet described above,
It is preferable that the bicontinuous phase structure and the sea-island structure exist in a positional relationship as shown in the conceptual diagram of FIG. That is, it is preferable that the layer (T ₁ ) near the center of thickness has a sea-island structure, and one or both of the surface layers (T ₂ ) is a bicontinuous phase. Further, in the thermoplastic resin sheet of the present invention, the thickness ratio of T ₁ and either one of T ₂ is preferably T ₁ / T ₂ =
1/50 to 50/1, particularly preferably 1/20 to
20/1.

The foamed thermoplastic resin sheet of the present invention can be formed into a laminate of two or more layers by laminating resin non-foamed sheets made of the same or different materials on one or both surfaces. This laminate can be manufactured in the same manner as in the case of the laminate of the thermoplastic resin sheet described above.

The container of the present invention is obtained by molding the above-described thermoplastic resin sheet or thermoplastic resin foam sheet of the present invention into a desired shape. The thermoplastic resin sheet and the thermoplastic resin foam sheet of the present invention have excellent tearability in the MD and TD directions, and particularly excellent in the MD direction, due to their phase structure. Therefore, the container of the present invention molded therefrom has a similar easy tearing property. In the present invention, the “container”
The meaning includes a main body and a lid. For example, in the case of a container for a side dish, the meaning includes a tray and a lid. The container of the present invention,
It is suitable as a food container that comes in contact with edible oil,
Of course, it is not limited to these, and various types of instant food containers of a type in which boiling water is poured, containers heated by a paper cup, a microwave oven, containers sterilized by heat during production and use, various non-heated containers, etc. Can also be applied.

[0035]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Examples 1 to 9 Using the resin composition comprising the compatibilizers of the components (A), (B) and (C) having the compositions shown in Table 1, a thermoplastic resin sheet was produced by the following method. did. In Table 1, (A),
The component (B) is expressed in terms of% by weight, and the component (C) is expressed in parts by weight based on the total amount of the components (A) and (B). The details of the component (A), the component (B), and the component (C) are as follows.

(A) Component GPPS: Styrene resin (“Daicel Styrol 51” manufactured by Daicel Chemical Industries, Ltd.) HIPS: High-impact polystyrene resin (“Daicel Styrol S85” manufactured by Daicel Chemical Industries, Ltd .; rubber content: 8 wt. %) SBS: Styrene-butadiene block copolymer (JS
"TR2003" manufactured by R Co., Ltd.) (B) component PP-1: polypropylene ("F109D" manufactured by Grand Polymer Co., Ltd.) PP-2: polypropylene ("F219D" manufactured by Grand Polymer Co., Ltd.) PP-3: polypropylene (“F769” manufactured by Grand Polymer Co., Ltd.) (C) Component (Compatibilizer) (C-3a): Styrene-ethylene-propylene-styrene copolymer (“Septon 2104” manufactured by Kuraray Co., Ltd.) 3b): Styrene-ethylene-butylene-styrene copolymer ("Clayton G165" manufactured by Shell Co., Ltd.)
0 ") (C-2a): Epoxy-modified styrene-butadiene copolymer (" Epofriend A10 "manufactured by Daicel Chemical Industries, Ltd.)
20 ") (C-2b): Hydrogenated epoxy-modified styrene-butadiene copolymer (JP-A-7-25984, page 2, column 2, 3)
A product obtained by hydrogenating Epofriend A1020 manufactured by Daicel Chemical Industries, Ltd. by the method described in lines 1 to 43).

After melting and kneading such a resin composition with a twin screw extruder (PCM30, manufactured by Ikegai Co., Ltd.), the extruded strand was cut to obtain resin pellets. An extruder (φ65 mm, L / D = 3)
The mixture was supplied to 2), melt-kneaded, and extruded from a T-die to obtain a thermoplastic resin sheet. In addition, as an example of molding conditions, Example 1 shows that the melting temperature of the resin composition is 210.
Extrusion was performed at 80 ° C. at a screw rotation speed of 80 rpm.

The obtained thermoplastic resin sheet was cut with an ultramicrotome so that the surface became smooth. After that, the cut surface is exposed to a vapor of a heavy metal oxide such as RuO ₄ or OsO ₄ to selectively dye only the styrene resin phase of the component (A). Observed with an electron microscope. (A) component or (B)
The part where the component can be confirmed as granular is defined as the sea-island structure, and the part where the component is not confirmed is defined as the bicontinuous phase structure.
As for the phase structure in the thickness direction of the sheet, it was confirmed that the layer (T ₁ ) near the center of the thickness had a sea-island structure and both surface layers (T ₂ ) had a bicontinuous phase structure. The thicknesses of the sea-island structure and the bicontinuous structure were measured in the same manner, and the ratio of T ₁ / T ₂ was calculated. FIG. 3 shows the surface layer (T) of the sheet of Example 2.
₂ ) A transmission electron micrograph (× 250) of a cross section in the MD direction of FIG.
0), FIG. 4 shows a transmission electron micrograph (× 2500) of a cross section in the TD direction of the surface layer (T ₂ ) of the sheet of Example 2, and FIG. 5 shows the layer (T ₁ ) near the center of the thickness. FIG. 6 shows a transmission electron micrograph (× 2500) of a cross section in the MD direction.
Shows a transmission electron micrograph (× 2500) of a cross section in the TD direction of the layer (T ₁ ) near the center of the thickness. 3 to 6, it was confirmed that both surface layers (T ₂ ) had a bicontinuous phase structure, and a layer (T ₁ ) near the center had a sea-island structure. Furthermore, tear strength, container moldability, and heat resistance were tested by the following methods. Table 1 shows the results.

(1) Tear Strength A thermoplastic resin sheet was punched out into a right-angled tear test specimen described in JIS K7128 to obtain a measurement sample. Using this measurement sample, measurement was performed at a test speed of 200 mm / min using Tensilon (RTA520; manufactured by Toyo Seiki).

(2) Container Formability Using a thermoplastic resin sheet, a single-shot vacuum forming machine manufactured by Asano Laboratories, an opening diameter of 90 mm, a bottom diameter of 80 mm, and a height of 50 mm.
A cup-shaped container having a diameter of mm was molded, and the container was visually observed for a corner (a portion where the bottom surface and the side surface are in contact) and a side surface torn and a surface condition (appearance and gloss), and evaluated according to the following criteria. ：: No breakage and good surface condition were obtained. Δ: No tear, but uneven unevenness on the surface. X: There was a break.

(3) Heat Resistance 100 g of commercially available salad oil was placed in a tray shown in FIG. 2 formed using a thermoplastic resin sheet, and heated in a microwave oven of 500 W for 5 minutes. The degree of deformation of the container after heating was visually observed and evaluated according to the following criteria. ：: No deformation, no melting marks on the surface. Δ: Some deformation was observed or melting marks were observed on the surface. ×: Deformation was large and melting marks were observed on the surface.

Comparative Examples 1 to 6 Thermoplastic resin sheets were obtained in the same manner as in Examples 1 to 9 using the components shown in Table 1. The same measurement as in Examples 1 to 9 was performed on these sheets. Table 1 shows the results.

[0044]

[Table 1]

As is evident from Table 1, the sheets of Examples 1 to 9 have a good balance between the sea-island structure and the bicontinuous phase structure in the inside and the surface layer. Heat resistance and oil resistance were also good. On the other hand, the sheets of Comparative Examples 1 to 6 were inferior in heat resistance and oil resistance due to poor balance between the sea-island structure and the bicontinuous phase structure in the inside and the surface layer.

Examples 10 to 19 Compositions shown in Table 2 (the same display criteria as in Table 1;
Using each of the components (A) to (C) (parts by weight based on the total amount of the components), a twin-screw extruder (PCM30, manufactured by Ikegai Corporation)
After melt-kneading, the extruded strands were cut to obtain resin pellets. One part by weight of mineral oil was spread on the resin pellets, and a mixture of sodium bicarbonate and sodium citrate (manufactured by Sankyo Chemical Co., Ltd .; CellMike 623) as a blowing agent was mixed in an amount shown in Table 2. A resin composition for a resin foam sheet was obtained. The resin pellets were supplied to an extruder (φ65 mm, L / D = 32), melt-kneaded, extruded from a T-die, and foamed to obtain a thermoplastic resin foam sheet. The conditions for obtaining the predetermined phase structure were the same as in Examples 1 to 9.
The same measurement as in Examples 1 to 9 was performed on these foam sheets. Table 2 shows the results.

Comparative Examples 7 to 10 Using the components shown in Table 2, thermoplastic resin foam sheets were obtained in the same manner as in Examples 10 to 19. The same measurement as in Examples 1 to 9 was performed on these foam sheets.
Table 2 shows the results.

[0048]

[Table 2]

As apparent from Table 2, Examples 10 to 1
The foamed sheet No. 9 had good tearability, good moldability, good heat resistance and good oil resistance because of the good balance between the sea-island structure and the bicontinuous phase structure in the interior and surface layers. On the other hand, the sheets of Comparative Examples 7 to 10 are poor in heat resistance and oil resistance or container moldability because the balance between the sea-island structure and the bicontinuous structure in the inside and the surface layer is poor.
10 was inferior in tearability.

[0050]

The thermoplastic resin sheet and the thermoplastic resin foam sheet of the present invention have excellent moldability, heat resistance and oil resistance, and are therefore suitable as materials for various containers. further,
Since the thermoplastic resin sheet and the thermoplastic resin foam sheet of the present invention have easy tearing properties, the containers obtained therefrom can be easily reduced in recovery, so that
The efficiency of the collection operation can be increased.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram for explaining a phase structure of a sheet according to the present invention.

FIG. 2 is a front view and a plan view of a tray formed in an example.

FIG. 3 is a transmission electron micrograph (× 2500) of a cross section in the MD direction of a surface layer of a sheet of the present invention.

FIG. 4 is a transmission electron micrograph (× 2500) of a cross section in the TD direction of a surface layer of the sheet of the present invention.

FIG. 5 is a transmission electron micrograph (× 2500) of a cross section in the MD direction of the center layer of the sheet of the present invention.

FIG. 6 is a transmission electron micrograph (× 2500) of a cross section in the TD direction of the center layer of the sheet of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08L 25:10 63:08 25:08) F term (Reference) 3E086 AD05 AD06 BA15 BA16 BB41 BB74 BB90 CA01 4F071 AA12X AA14 AA22 AA22X AA31X AA78 AE22 AF02 AF16 AF45 AH05 BA01 BB06 BC01 BC10 BC12 4J002 BB03X BB05X BB10X BB12X BB14X BB15X BB17X BC03W BC04Y BC05W BC05Y BC06W BC07Y BC08 BC09YBC09W BC08Y BC09 BC09Y

Claims (10)

[Claims] 1. A sheet obtained from a resin composition containing (A) 3 to 97% by weight of a styrene-based resin and (B) 97 to 3% by weight of an olefin-based resin. B) A thermoplastic resin sheet wherein the component forms a bicontinuous phase structure and a sea-island structure. 2. The heat according to claim 1, wherein the resin composition further comprises at least one compatibilizer selected from the following (C-1) to (C-4) as the component (C). Plastic resin sheet. (C-1) a copolymer of a vinyl aromatic compound and a conjugated diene compound or a hydrogenated product thereof; (C-2) an epoxidized product of a copolymer of a vinyl aromatic compound and a conjugated diene compound; or (C-3) a copolymer of a styrene monomer serving as a constituent unit of the component (A) and a monomer serving as a constituent unit of the component (B), and (C-4) a vinyl aromatic compound. , A copolymer with a compound having a carboxyl group or an acid anhydride. 3. The phase structure in the thickness direction of the sheet, wherein a layer near the center of the thickness has a sea-island structure (T ₁ ), and at least one surface layer has a bicontinuous phase structure (T ₂ ). The thermoplastic resin sheet according to the above. 4. The thickness ratio between the layer (T ₁ ) near the center and one of the surface layers (T ₂ ) is T ₁ / T ₂ = 1/50 to 50.
The thermoplastic resin sheet according to claim 3, wherein the ratio is / 1. 5. A container comprising the thermoplastic resin sheet according to claim 1. 6. A foamed sheet obtained by foam-forming the resin composition according to claim 1 or 2, wherein the component (A) and the component (B) form a bicontinuous phase structure and a sea-island structure in the foamed sheet. A thermoplastic resin foam sheet characterized in that: 7. The thermoplastic resin foam sheet according to claim 6, wherein the expansion ratio is 1.1 to 3.0 times. 8. The thermoplastic resin sheet according to claim 6, wherein the phase structure in the thickness direction of the sheet is such that a layer near the center of the thickness has a sea-island structure, and at least one surface layer has a bicontinuous phase structure. 9. The thickness ratio between the layer (T ₁ ) near the center and one of the surface layers (T ₂ ) is T ₁ / T ₂ = 1/50 to 50.
The thermoplastic resin sheet according to claim 8, wherein the ratio is / 1. 10. A container comprising the thermoplastic resin foam sheet according to any one of claims 6 to 9.