JPH0518955A - Analytical element - Google Patents

Abstract

PURPOSE:To improve the productivity of an expanding layer without deteriorating its function by forming the expanding layer of fibers and binder resin and using a hydrophobic high polymer material having at least a urethane group as the binder resin. CONSTITUTION:An expanding layer is formed of fibers which can pass through a 50-mesh screen but cannot pass through a 325-mesh screen and a binder resin which is composed of a hydrophobic high polymer material having at least a urethane group. As a result, the expanding layer has an excellent film adhering property, resistance to cracking, and film strength. Therefore, the productivity of the expanding layer can be improved, because no special adhesive layer is required, and the cost of the expanding layer can be reduced, since the occurrence of unacceptable products can be reduced at the time of cutting the layer. In addition, the pore of the expanding layer is not filled up with the binder resin and the expanding layer can sufficiently exert its function, because the amount of the resin can be controlled to a required amount. Furthermore, the expanding layer can also be improved in simultaneous reproducibility.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an analytical element for analyzing a specific component in a liquid sample, and more particularly to a multi-layer analytical element provided with a porous developing layer useful for a clinical test using a liquid as a sample. .

[0002]

BACKGROUND OF THE INVENTION Conventionally, as one form of a dry type analytical element, a water-absorbing reagent layer containing a color reaction reagent and a hydrophilic polymer (binder) and a porous layer are provided on a liquid-impermeable and transparent support. There has been proposed an integrated multi-layer analysis element provided with a property spreading layer. The porous spreading layer in this analytical element is
Aqueous liquid sample that has been spotted (eg, whole blood, plasma, serum,
Lymph, saliva, cerebrospinal fluid, vaginal fluid, urine, liquor, drainage, etc.) can be laterally spread without substantially unevenly distributing the components contained in the aqueous liquid sample, and the reagent can be used at a constant rate per unit area. It is a layer that has a function of diffusing into the layer (metering function). Incidentally, the porous spreading layer having such a function is described in US Pat.
9-53888, JP-A-55-164356, JP-A-57-66359, and JP-A-57-12.
5847, JP-A-57-197466 and the like.

By the way, since a hydrophobic binder resin is used for the porous spreading layer provided on the reagent layer containing a hydrophilic polymer, the adhesiveness is weak, and therefore the reagent layer and the porous spreading layer are weak. It has been proposed to provide an adhesive layer between and. However, the technical means of specially providing the adhesive layer causes a decrease in productivity and an increase in cost.

[0004]

DISCLOSURE OF THE INVENTION The object of the present invention is that the film-forming property is good, the cracking resistance is excellent, the coating film strength is excellent, the function as a developing layer is sufficiently exhibited, and the simultaneous reproducibility is excellent. It is to provide analytical elements with high productivity. An object of the present invention is an analytical element in which a reagent layer containing at least one reagent is provided on a support, and a development layer is provided above the analysis layer, the development layer containing fibers and a binder resin. This is achieved by an analytical element characterized in that a hydrophobic polymer having at least a urethane group is used as the binder resin.

Fibers that pass through a 50-mesh screen and do not pass through a 325-mesh screen are preferably used. Also provided is a reagent layer containing at least one reagent on a support, which is an analytical element having a spreading layer provided thereon, wherein the spreading layer contains short fibers and a binder resin, This is achieved by an analytical element characterized in that a hydrophobic polymer having at least a urethane group is used as the binder resin.

It should be noted that when passing through a 325 mesh sieve, the average value of the length in the longitudinal direction is 1 to 200 μm, and the average value of the length in the longitudinal direction / the length in the lateral direction is 1.1 to 10 as short. Fibers are preferably used. Further, a reagent layer containing at least one reagent is provided on a support, an analytical element comprising a spreading layer provided thereon, wherein the spreading layer contains a non-fiber and a binder resin, This is achieved by an analytical element characterized in that a hydrophobic polymer having at least a urethane group is used as the binder resin.

The non-fiber is preferably crystalline cellulose.
Then, the analytical element of the present invention configured as described above,
Since the spreading layer has good film adhesion, excellent cracking resistance, and excellent coating strength, it is no longer necessary to provide a special adhesive layer as in the past, and productivity is improved accordingly. Moreover, the number of defective products due to cutting is significantly reduced, the cost of the analysis element is low, and more binder resin is not required more than necessary, so the voids in the development layer are filled with the binder resin. In this case, the function as a spreading layer is fully exerted, and the features of excellent simultaneous reproducibility are exhibited.

The analytical element of the present invention will be described in more detail below. The support for the analytical element of the present invention,
Any type of polymer material such as cellulose acetate, polyethylene terephthalate, polycarbonate, polystyrene can be used as long as it is liquid impermeable and light transmissive. The thickness of the support is arbitrary, but it is preferably about 50 to 250 μm. One side surface of the support on the observation side can be optionally processed according to its purpose.

When the reagent layer is provided on the support, the reagent layer can be directly provided, but in some cases, a light-transmitting undercoat layer is provided to enhance the adhesiveness between the reagent layer and the support. You may do it. The reagent layer is provided to contain the reagents to be quantitatively reacted with the sample component to be analyzed and to perform the quantitative reaction. Since this reagent layer is provided by coating the support with a hydrophilic colloid substance as a binder, it is necessary to uniformly contain the reagents, unlike the conventional case in which a carrier such as a filter paper is impregnated with the reagent. And has the advantage that the content of the reagent can be freely controlled. As such a hydrophilic colloidal substance, a natural or synthetic polymer substance is preferable, and more desirably, a gelatin derivative such as gelatin or modified gelatin, polyvinyl alcohol, polyvinylpyrrolidone or the like is preferable. Among these, gelatin derivatives such as gelatin are particularly preferable. These hydrophilic colloid materials preferably have a degree of swelling of about 150-500%. The film thickness can be selected as desired, and is preferably at least about 5 μm or more.

It goes without saying that the reagent contained in the reagent layer constructed as described above depends on the analyte component to be analyzed in the sample and the analysis reaction selected for analyzing this component. When the selected analytical reaction is composed of two or more kinds of reagents, the reagents may be mixed and contained together in the same reagent layer, or two or more kinds of reagents may be formed in different layers. It may be contained. It is also possible to carry out an analysis reaction of two or more kinds of analyte components in a sample in the same reagent layer. At this time, it is desirable to select the analysis reactions so that two or more kinds of analysis reactions do not interfere with each other and do not affect each other when measuring the reaction products formed.

In the present invention, one or a plurality of spreading layers are provided above the reagent layer provided on the support. This spreading layer is provided for the following purposes. (1) A constant volume of a fluid sample is uniformly dispersed per unit area in a reagent layer. (2) It may have a function of removing a substance or a factor that inhibits the analysis reaction in the fluid sample, if necessary. (3) When performing the spectrophotometric analysis, a function of performing a background action of reflecting the measurement light passing through the support may also be provided.

Therefore, the spreading layer according to the present invention may be configured so that one layer can exhibit all of the above-mentioned three functions, or each function is appropriately separated, and a separate layer is formed for each function. May be. Furthermore, of the three functions
You may make it combine the layer which exhibits two functions, and the layer which exhibits the remaining other function. The film thickness of the spreading layer according to the present invention can be arbitrarily selected according to the purpose,
Preferably about 20-600 μm, more preferably 50.
˜400 μm. The porosity of the spreading layer is preferably 25 to 90%, more preferably 40 to 80%. The average pore size of the development layer is preferably 1 to
200 μm, more preferably 3 to 150 μm, and even more preferably 5 to 100 μm.

The fiber used in the present invention is a fiber having a fibrous shape, for example, JP-A-57-197466.
The fibers disclosed in the publication, natural cellulose, and derivatives thereof, and synthetic fibers such as polyethylene, polypropylene and polyamide are listed. Incidentally, this fiber passed through the JIS standard sieve 50 mesh and could not pass through the JIS standard sieve 325 mesh, and more desirably, the fiber which passed through the JIS standard sieve 100 mesh and could not pass through the JIS standard sieve 320 mesh, It is more preferable that the material can pass through the JIS standard sieve 200 mesh and cannot pass through the JIS standard sieve 300 mesh. In particular, natural cellulose having the above size is preferable.

The short fibers used in the present invention are those which can pass through the JIS standard sieve 325 mesh, and are not spherical in shape, but have a needle-like shape having a major axis and a minor axis. It is different from the material for forming the non-fibrous porous medium disclosed in Japanese Laid-Open Patent Publication No. 49-53888, and also different from the fiber disclosed in Japanese Laid-Open Patent Publication No. 57-125847. A spreading layer constructed by using such short fibers is disclosed in, for example, JP-A-49-538.
No. 88 disclosed in Japanese Unexamined Patent Publication No. 88-125847 and the fibrous porous developed layer disclosed in JP-A-57-125847 have the respective features, and each of them has drawbacks. It will be resolved.

The short fibers pass through a 325 mesh screen,
The average value of the length in the longitudinal direction is 1 to 200 μm, and it is preferable to use the short fibers having the average value of the length in the longitudinal direction / the length in the lateral direction of 1.1 to 10, but the length in the longitudinal direction. The average value of 1 to 150 μm, more preferably 5 to 150 μm, further preferably 5 to 100 μm, and more preferably 10
It is even more preferable that the average value of the length in the longitudinal direction / the length in the lateral direction is 1.1 to 5, and more preferably 1.2 to 3 at 100 μm.

Such short fibers include, for example, natural cellulose and its derivatives, polyethylene, polypropylene,
It can be obtained by treating a crushed product of synthetic fibers such as polyester, polyamide and polyurethane with a sieve of 325 mesh or more. Further, for example, crystalline cellulose such as Avicel manufactured by Asahi Kasei Co., Ltd., and a crushed resin product can be used, and the crushed fiber product is not limited. It is particularly preferable to use natural cellulose.

The non-fiber used in the present invention means a non-fibrous shape, for example, JP-A-49-53888.
Materials for forming the non-fibrous porous media disclosed in the publication, for example, inorganic pigments such as titanium dioxide, barium sulfate, diatomaceous earth, microcrystalline colloid products derived from natural or synthetic polymers, Examples thereof include microcrystalline cellulose such as Avicel manufactured by FMC, and inert particles such as glass beads and resin beads, and particularly preferably microcrystalline cellulose.

The method for forming the porous spreading layer using fibers, short fibers or non-fibers is, for example, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinylidene chloride copolymer,
Vinyl chloride-acrylonitrile copolymer, acrylic acid ester-acrylonitrile copolymer, acrylic acid ester-vinylidene chloride copolymer, acrylic acid ester-styrene copolymer, methacrylic acid ester-acrylonitrile copolymer, methacrylic acid ester-chloride Vinylidene copolymer, methacrylic acid ester-styrene copolymer,
Nylon-silicon resin, nitrocellulose-polyamide resin, polyvinyl fluoride, vinylidene chloride-acrylonitrile copolymer, butadiene-acrylonitrile copolymer, polyamide resin, polyvinyl butyral, cellulose derivative (cellulose acetate butyrate, cellulose diacetate, cellulose Other adhesives such as triacetate, cellulose propionate, nitrocellulose, etc., styrene-butadiene copolymer, polyester resin, chlorovinyl ether-acrylic acid ester copolymer, amino resin, various synthetic rubber thermoplastic resins, etc. ,
Polymers disclosed on pages 9 to 13 of JP-A-55-90859, JP-A-57-1974
The polymer disclosed on page 5 to page 7 of Japanese Patent Publication No. 66, the reactive hydrophobic polymer described in Japanese Patent Publication No. 199006/1990 can be used, but the resin of the reagent layer is
In particular, considering the adhesiveness with gelatin or a gelatin derivative, it is important to use at least a hydrophobic polymer having a urethane group.

Examples of the hydrophobic polymer having a urethane group include a polyurethane resin and a urethane urea resin which are soluble in an organic solvent. Of these, a thermoplastic polyurethane resin soluble in an organic solvent is preferable. Specific examples of such a material include, for example, polyurethane resin ESTANE5703 / 5703P manufactured by Goodrich Co., USA.
(MW120,000, Tg = -35 ° C, polyester type polyurethane), 5701F1 / 5701P (MW
140000, Tg = -25 ° C, polyester type polyurethane), 5707F1 (MW130000, Tg
= -17 ° C, polyester type polyurethane), 57
07F (MW120,000, Tg = -32 ° C, polyester type polyurethane), 5715 (MW7300
0, Tg = -51 ° C, polyester type polyurethane), K-1335 (MW65000, Tg = 95 ° C,
Polyester type polyurethane), 5714F1 (M
W140000, Tg = -50 ° C, polyether type polyurethane) and the like. The thermoplastic polyurethane resin soluble in an organic solvent comprises diisocyanate, a polymer diol and a chain extender, and various properties can be obtained depending on the kind and amount of these. In the present invention, the diisocyanate, the polymer diol, and the chain extender may be any ones as long as they are soluble in an organic solvent and are not limited. The molecular weight is preferably 10,000 to 150,000, and more preferably 30,000 to 150,000. Also, Tg is -100 ° C to 100 ° C, preferably-
It is preferably 100 ° C to 50 ° C. The proportion of urethane bonds present is 1 when expressed in mol% of diisocyanate.
-30 mol%, desirably 1-20 mol% is preferable.

The binder may be used in widely selected amounts, but a substantial portion of the interstitial volume formed by the fibers, staple fibers or non-fibers is relative to the fibers, staple fibers or non-fibers. 0.05 to 50% by weight, more preferably 0.05 to 30% by weight can be used. The spreading layer of the present invention can be manufactured using various methods. For example, a spreading layer can be formed by dispersing fibers, short fibers or non-fibers in a liquid carrier that does not dissolve, then adding the binder to prepare the fiber, short fibers or non-fibers dispersion, and then coating and drying. it can.

Dispersions useful for forming the spreading layer must be stable for a sufficient time. Many methods can be used alone or in combination to produce such a stable dispersion. For example, one useful method is to add a surfactant to a liquid carrier,
Dispersion and stabilization in a dispersion of short fibers or non-fibers can be promoted.

Examples of typical surfactants that can be used include cationic or anionic surfactants, Triton X-100 (Rohm and Haas Co., Octylphenoxypolyethoxyethanol), Surfactant 1
There are nonionic surfactants such as 0G (Nonylphenoxypolyglycidol, manufactured by Olein Co.). These surfactants may be used in widely selected amounts, but may range from 0.005 to fiber, staple fiber or non-fiber.
It is preferable to use 30% by weight, more preferably 0.05 to 20% by weight.

As another method, there are ultrasonic treatment, physical mixing, physical stirring treatment, and pH adjustment of the above dispersion liquid,
It is effective to combine these with the above method.
The liquid carrier of the fiber, chopped fiber or non-fiber dispersion may be a water-miscible organic solvent, an aqueous mixture of water and a water-miscible organic solvent and a suitable water-immiscible organic solvent. Water-miscible organic solvents include lower alcohols (alcohols having 1 to 4 carbon atoms in the alkyl group), acetone, methyl ethyl ketone and tetrahydrofuran. Water-immiscible solvents include lower alkyl esters such as ethyl acetate, halogenated organic solvents such as halogenated hydrocarbons (eg chloroform, methyl chloride and carbon tetrachloride, etc.), aromatic hydrocarbons (eg benzene, toluene and There are solvents such as xylene) and aliphatic hydrocarbons (eg hexane, decalin etc.).

The analytical element of the present invention may have various functional layers, reagent layers and members, for example, US Pat.
No. 58, the reagent layer, the filtration layer, the reflection layer, the undercoat layer,
Radiation blocking layer described in US Pat. No. 4,042,335, barrier layer described in US Pat. No. 4,066,403, registration layer described in US Pat. No. 4,144,306, migration prevention layer described in US Pat. No. 4,166,093. U.S. Pat. No. 4,127
Scintillation layer described in Japanese Patent Publication No. 499, JP-A-55
The scavenger layer described in Japanese Patent No. 90859 and the destructible pod-shaped member described in U.S. Pat. No. 4,111,079 can be arbitrarily combined to form an analytical element.

In the analytical element having the spreading layer of the present invention, the smoothing of the surface of the spreading layer is increased by carrying out calendering treatment by a method of passing between a pair of pressure rollers, and a preferable effect in optical reflection is obtained. It is possible to obtain. The analysis element of the present invention can be obtained, for example, by a dip coating method, an air knife method, a curtain coating method or US Pat.
It can be coated by various coating methods such as extrusion coating using a hopper as described in US Pat. No. 294, and if desired two or more layers can be coated.
It is also possible to apply simultaneously by the method described in No. 1 and British Patent No. 837095.

The analytical element of the present invention can achieve the object by supplying a fluid sample from the developing layer side and observing from the transparent support side. The amount of the fluid sample applied to the analytical element of the present invention can be arbitrarily determined, but is preferably about 5
˜50 μl, more preferably about 5-20 μl. It is usually preferred to apply about 10 μl of fluid sample.

The analytical reaction used in the analytical element of the present invention can be arbitrarily determined depending on its purpose. For example, biological reactions such as whole blood, plasma, serum, lymph, saliva, spinal fluid, vaginal fluid, and urine. Used for analysis of components in fluid samples.
By appropriately selecting an analytical reagent, for example, glucose, urea nitrogen, ammonia, uric acid, cholesterol,
It can be readily configured for use in components such as triglycerides, creatine, creatinine, bilirubin as well as many other analyses.

The analytical element of the present invention is applicable not only to the field of clinical chemistry but also to other fields of chemical analysis, and has the function of retaining a constant fluid within a constant membrane area. It is also possible to combine with other functional layers. After obtaining the analysis result as a detectable change using the analytical element of the present invention, reflection spectrophotometry, transmission spectrophotometry, emission spectrophotometry or fluorescence spectrophotometry or corresponding to various detectable changes. It is measured by scintillation measurement or the like. The measurement value thus obtained is
The amount of the unknown test substance can be determined by applying it to the calibration curve prepared in advance.

Hereinafter, the present invention will be described more specifically with reference to examples.

[0030]

【Example】

Example 1 A reagent layer having the following composition was provided on a transparent subbed polyethylene terephthalate support having a film thickness of 180 μm. Reagents Layer] Gelatin 14.0 g / m ² 1,7- dihydroxynaphthalene 0.84 g / m ² 4-aminoantipyrine villin hydrochloride 0.81 g / m ² dimedone 0.19 g / m ² Potassium phosphate buffer (pH 6.1) 2.82 g / m ² sodium triisopropyl naphthalene sulfonate 0.22 g / m ² 1,2-bis (vinylsulfonyl) ethane 0.10 g / m ² peroxidase 12500U / m ² glucose oxidase 45000U / m ² On the other hand, as a fiber material (F1), a filter paper powder D manufactured by Toyo Roshi Kaisha, Ltd. (passing through a 40-mesh sieve and not passing through a 100-mesh sieve) was prepared. Also, short fiber material (F2)
As the material, a filter paper powder manufactured by Toyo Roshi Kaisha, Ltd. was classified with a sieve of 350 mesh or more. Crystalline cellulose "Avicel" as a non-fiber material (F3) (pH 1 manufactured by Asahi Kasei Corporation)
01) was used.

Polyurethane resin ESTANE5701F (urethane group-containing hydrophobic polymer, B1) manufactured by Goodrich, USA, and polyurethane resin ESTANE5714F1 (urethane group-containing hydrophobic polymer, B2) manufactured by Goodrich, USA, and styrene-glycidyl meta are used as the binder resin. An acrylate (90/10) copolymer (hydrophobic polymer not containing urethane group, B3) was prepared.

Then, these F1, F2, F3 and B
1, B2 and B3 were used to prepare dispersion liquids for forming a spreading layer shown in Table 1. Table 1 Porous structure molding material Binder resin Liquid carrier Surfactant dispersion 1 F1 100g B1 15g MEK 308g Triton X100 10g Dispersion 2 F1 100g B2 15g MEK 308g Triton X100 10g Dispersion 3 F2 100g B1 15g 10k MEK 308g Dispersion 4 F2 100g B2 15g MEK 308g Triton X100 10g Dispersion 5 F3 100g B1 15g MEK 308g Triton X100 10g Dispersion 6 F3 100g B2 15g MEK 308g Triton X100 10g Dispersion 7 B3 10g 15F 100g 15L 10g 8 F2 100 g B3 15 g Xylene 308 g Triton X100 10 g Dispersion 9 F3 100 g B3 15 g Xylene 308 g Triton X100 10 g Then, the development area when 10 μl spotted on the reagent layer is 0.7 to 0.8 cm. Dispersions 1 to 9 are applied so as to be ² and dried, and then the analysis elements 1 to 6 of the present invention (dispersions 1 to 6)
And Analytical elements 1 to 3 (dispersions 7 to 9) of Comparative Example were prepared.

Human serum having various glucose concentrations of 10 μm was applied to the analytical elements 1 to 6 of the present invention and the analytical elements 1 to 3 of the comparative example.
After spotting 1 point and incubating at 37 ° C for 7 minutes,
The reflection density was measured using a 546 nm filter, and the reflection density and Unikit Glucose E (Chugai Pharmaceutical Co., Ltd.)
A calibration curve was prepared in advance from the human serum glucose concentration assayed in.

Furthermore, the normal value (87 m
g / dl) and an abnormal value (280 mg / dl) were spotted each 18 times, the same operation as described above was performed, and the glucose concentration was calculated by fitting the calibration curve to obtain the coefficient of variation CV (%). Further, with respect to the analysis elements 1 to 6 of the present invention and the analysis elements 1 to 3 of the comparative example, the coated sample was cut into a strip-shaped sample of 1 cm × 7 cm, and the degree of interfacial peeling between the spreading layer and the base when cut, The occurrence of cracks in the spreading layer when the strip-shaped sample was bent with a finger was visually evaluated. The results are shown in Table 2.

Table 2 Normal value Abnormal value X (mg / dl) CV (%) X (mg / dl) CV (%) Membrane property Cracking degree Inventive analytical element 1 87 2.11 280 2.09 ◎ ◎ Inventive analytical element 2 87 2.09 280 2.00 ◎ ◎ Inventive Analytical Element 3 87 1.23 280 1.19 ◎ ◎ Inventive Analytical Element 4 87 1.89 280 1.77 ◎ ◎ Inventive Analytical Element 5 87 1.11 280 1.02 ◎ ◎ Inventive Analytical Element 6 87 1.46 280 1.23 ◎ ◎ Comparative Example Analytical Element 1 87 2.45 280 2.33 × × Comparative Example Analytical Element 2 87 1.99 280 1.91 △ △ Comparative Example Analytical Element 3 87 1.43 280 1.21 △ △ Remark) Film coatability ◎ Very good ○ Good △ Somewhat bad × Defect Cracking degree ◎ Extremely good (no cracks occurred) ○ Good △ Somewhat bad × Bad (large cracks are recognized) From Table 2, the analytical element of the present invention has good simultaneous reproducibility and is a hinder of the lower layer of the spreading layer. It can be seen that the resin has excellent adhesiveness even though the resin is a hydrophilic polymer. Thus, since the analytical element of the present invention has excellent adhesiveness, film peeling is unlikely to occur during cutting even if an adhesive layer is not provided, and the occurrence of cutting debris is extremely small, and an excellent quality analytical element Can be provided at low cost.
Furthermore, since it has appropriate flexibility, no cracks are observed on the surface of the spreading layer even when the analytical element of the present invention is deformed. When the coated product is transported, it is possible to wind and transport the coated product, which is excellent in productivity.

Example 2 A dispersion having the composition shown in Table 3 was prepared. Table 3 Porous Structure Molding Material Binder Resin Liquid Carrier Surfactant Dispersion 10 F1 100g B1 5g MEK 308g Triton X100 10g Dispersion 11 F1 100g B1 10g MEK 308g Triton X100 10g Dispersion 12 F1 100g B1 15g 10k MEK 308g Dispersion 13 F1 100g B1 20g MEK 308g Triton X100 10g Dispersion 14 F1 100g B1 25g MEK 308g Triton X100 10g Dispersion 15 F1 100g B3 5g MEK 308g Triton X100 10g Dispersion 16 B3 10g Dispersion 16 F3 10g 10F 100g 17 F1 100g B3 15g Xylene 308g Triton X100 10g Dispersion 18 F1 100g B3 20g Xylene 308g Triton X100 10g Dispersion 19 F1 100g B3 25g Xylene 308g Triton X100 10g Dispersion 10 above Glucose analysis element (analysis elements 7 to 11 of the present invention (use of dispersion liquids 10 to 14) and analysis elements 4 to 8 of comparison example (use of dispersion liquids 15 to 19)) using 9 in the same manner as in Example 1. It was created.

The analytical element 7 of the present invention thus obtained
With respect to 11 and the analytical elements 4 to 8 of the comparative example, the film forming property and the cracking degree were evaluated in the same manner as in Example 1. Further, the surface of the spreading layer was scratched with a pencil having a hardness of H to evaluate the film strength. The results are shown in Table 4. Table 4 Membrane property Cracking degree Film strength Analytical element 7 of the present invention ◎ ○ △ Analytical element 8 of the present invention 8 ◎ ○ ○ Analytical element 9 of the present invention ◎ ○ ○ Analytical element 10 of the present invention ◎ ○ ○ Analytical element of the present invention 11 ◎ ○ ○ Comparative analysis element 4 × × × Comparative analysis element 5 × × × Comparative analysis element 6 △ × △ Comparative analysis element 7 △ × ○ Comparative analysis element 8 × × From Table 4, when a hydrophobic polymer having a urethane group in the molecular chain is used as a binder, even if it is a small amount, it has good film-forming property, excellent cracking resistance, and excellent coating strength. It can be seen that a layered analytical element is obtained.

On the other hand, when a hydrophobic polymer having no urethane group is used, if it is not used in a large amount, a large amount such as 25% by weight is used when the porous structural molding material is a fiber. If this is not done, the binder function will be inadequate, however, when used in such a large amount, the voids of the spreading layer will be filled with the binder resin, and the function as the spreading layer will not be exhibited. Then, since the voids are filled, the film thickness of the development layer must be increased in order to obtain the development area, which results in a large value of the film thickness of the entire device, which lowers the productivity. Problems also arise.

Claims (6)

[Claims] 1. An analysis element comprising a support and a reagent layer containing at least one reagent, and a spreading layer provided above the reagent layer, wherein the spreading layer contains fibers and a binder resin. The analytical element is characterized in that a hydrophobic polymer having at least a urethane group is used as the binder resin. 2. The analysis element according to claim 1, wherein a fiber that passes through a 50-mesh screen and does not pass through a 325-mesh screen is used. 3. An analytical element comprising a support and a reagent layer containing at least one reagent, and a spreading layer provided above the reagent layer, wherein the spreading layer contains short fibers and a binder resin. An analytical element characterized in that a hydrophobic polymer having at least a urethane group is used as the binder resin. 4. A 325 mesh sieve having an average length in the longitudinal direction of 1 to 200 μm and a length in the longitudinal direction /
The analysis element according to claim 3, wherein short fibers having an average length in the width direction of 1.1 to 10 are used. 5. An analysis element comprising a support and a reagent layer containing at least one reagent provided thereon, and a development layer provided above the reagent layer, wherein the development layer contains a non-fiber and a binder resin. An analytical element characterized in that a hydrophobic polymer having at least a urethane group is used as the binder resin. 6. The analytical element according to claim 5, wherein the non-fiber is crystalline cellulose.