JP2018132116A - Packing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a packing having excellent sealability.SOLUTION: In a packing, a polyurethane elastic body containing a thermosetting polyurethane and a filler is used to form at least a slide contact face, and on the rear side of the slide contact face, provided is a low concentration region with a lower filler concentration than that of the slide contact face.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a packing, and more particularly to a packing provided with an elastic member.

Conventionally, sealing materials such as gaskets and packings have been widely used.
Among these, while the mating member sealed by the gasket is in a stationary state in principle, the packing is used in a form of sliding contact with the mating member that moves relative to the packing.
The conventional packing is provided with an elastic member that exhibits elastic deformation, and a repulsive force against the elastic deformation of the elastic member is used as a contact pressure with respect to the counterpart member.
Regarding such packing, Patent Document 1 described below describes the use of an elastic member made of thermoplastic polyurethane (see paragraph 0033 and the like).
Polyurethane is a polymer obtained by the reaction of a monomer having an active hydrogen such as a polyol and a monomer having an isocyanate group such as a polyisocyanate, and has a variety of monomer species that can be selected as a starting material, and thus meets the required characteristics. It is superior to other general polymers in that it is easy to produce an elastic body.

JP 2006-057834 A

For conventional packings, it is required to exhibit excellent sealing properties with a mating member to be slidably contacted.
Regarding such a demand, it is conceivable to improve the contact pressure to the mating member by improving the resilience to elastic deformation.
However, if a strong contact pressure acts on the sliding contact surface that is slidably contacted with the mating member, there is a risk that the sliding contact surface is likely to be worn.
When the packing is worn on the sliding contact surface, the sealing performance may be lowered.
For this reason, it is considered effective to employ an elastic member having excellent wear resistance in order to satisfy the above demand.

  This invention makes it a subject to satisfy the above requests, and makes it a subject to provide the packing excellent in the sealing performance.

  As a result of intensive studies by the inventor in order to solve the above-described problems, a sliding contact surface is formed by a polyurethane elastic body containing a thermosetting polyurethane and a filler, and the filler concentration is lower than the filler concentration on the sliding contact surface. The present invention has been completed by finding that the above problem can be solved by providing the region on the back side of the sliding surface.

  That is, the present invention for solving the above problems is a packing provided with an elastic member, the elastic member having a sliding contact surface in sliding contact with a mating member and containing a thermosetting polyurethane and a filler. At least the sliding contact surface is formed by an elastic body, and the polyurethane elastic body is provided with a low concentration region having a filler concentration lower than the concentration of the filler on the sliding contact surface on the back side of the sliding contact surface. Provide packing.

  ADVANTAGE OF THE INVENTION According to this invention, since a sliding contact surface is formed with the polyurethane elastic body excellent in abrasion resistance, the packing excellent in the sealing performance can be provided.

The schematic perspective view which showed packing of one Embodiment, and a partial enlarged view. Schematic which showed the use condition of the packing shown in FIG. The schematic perspective view (a) which showed packing of other embodiment, and the AA arrow directional cross-sectional view shown in the said perspective view (b). Schematic which showed the use condition of the packing shown in FIG.

The preferred embodiments of the present invention will be described below.
First, as a first embodiment of the present invention, a case where a string-like packing is used as a gland packing will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic perspective view showing the packing according to the first embodiment. In the following, the vertical direction in FIG. 1 is referred to as the packing thickness direction T, and the lateral direction is referred to as the packing width direction W. is there.
In addition, the direction perpendicular to both the thickness direction T and the width direction W (the direction indicated by the symbol L in FIG. 1) may be referred to as the packing length direction L below.

The packing 1 of this embodiment is provided with the elastic member which contacts an other party member in the state deform | transformed elastically.
The packing 1 of this embodiment does not have a special structural member other than the elastic member 10 configured by a polyurethane elastic body, and is configured only by the polyurethane elastic body.
The packing 1 of the present embodiment includes a string-like elastic member 10 having a rectangular cross section.
That is, the packing 1 has a rectangular cross-sectional shape when cut along a plane orthogonal to the length direction L as shown in FIG. 1, and the dimension in the width direction W is larger than the dimension in the thickness direction T. Has a small vertical rectangular cross-sectional shape.
The elastic member 10 has a first surface 10a and a second surface 10b that face each other in the thickness direction T, and at least the first surface 10a is a sliding contact surface that is in sliding contact with a mating member that is sealed. .
As will be described later, the elastic member has at least the sliding contact surface formed of a polyurethane elastic body containing a thermosetting polyurethane and a filler, and the polyurethane elastic body has a concentration of the filler on the sliding contact surface. A low concentration region having a lower filler concentration is provided on the back side of the sliding contact surface.
The elastic member 10 of the present embodiment has a high concentration region 10s with a relatively high filler concentration on the first surface 10a side and a low concentration with a low filler concentration on the second surface 10b side compared to the high concentration region 10s. A region 10t is provided.

In the elastic member 10 of the present embodiment, the boundary between the high concentration region 10s and the low concentration region 10t is not clear, and the concentration of the filler is inclined in one direction in the thickness direction T.
That is, the elastic member 10 of this embodiment is provided with a filler concentration gradient so that the filler concentration gradually increases from the second surface 10b toward the first surface 10a. As a result, the low concentration region is provided on the back side of the sliding contact surface.

The packing 1 is used, for example, in a manner as shown in FIG. 2, and is used as a gland packing for the purpose of dynamic sealing of an apparatus having a rotating body.
The apparatus 100 includes a casing 110, and the casing 110 is provided with a columnar through hole 110a arranged in a direction penetrating the wall.
In addition, a packing box 130 is provided outside the housing 110 so as to penetrate the wall together with the through hole 110a.
That is, the through hole 110a is opened on the inner wall surface of the housing, while the packing box 130 is opened on the outer wall surface of the housing.
The packing box 130 has a cylindrical space that is slightly larger than the through hole 110a.
The packing box 130 and the through hole 110a are arranged side by side along a direction penetrating the wall of the housing 110, and are arranged so that their central axes are aligned in a straight line.
The hole penetrating the wall of the housing 110 is greatly reduced in diameter at the connecting portion between the packing box and the through hole 110a when viewed from the outside to the inside, and the hole between the through hole 110a and the packing box 130 is A step is formed at the boundary.
That is, a ring plane that extends in a direction orthogonal to the rotation shaft 120 at the boundary between the through hole 110a and the packing box 130 of the housing 110 and has an annular shape when viewed in the rotation axis direction. 110b is provided.
The rotating shaft 120 of the rotating body extends from the through hole 110 a through the center of the packing box 130, and an end of the rotating shaft 120 reaches the outside of the opening 130 a of the packing box 130.
The opening 130 a of the packing box 130 serves as an accommodation port for accommodating the packing 1 (gland packing) of the present embodiment in the packing box 130, and the ring plane 110 b is the packing 1 accommodated in the packing box 130. It is a pedestal to receive.

The apparatus 100 has a ring-shaped packing retainer 140 having an inner diameter through which the rotary shaft 120 can be inserted and having an outer shape slightly smaller than the opening diameter of the packing box 130.
The packing 1 according to this embodiment is wound around the rotary shaft 120 in a spiral manner so that the first surface 10a is in contact with the rotary shaft 120, and the side surfaces 10c and 10d are in close contact with each other in the axial direction of the rotary shaft 120. Housed in the packing box 130.
That is, the packing 1 has a cylindrical shape as a whole and is accommodated in the packing box 130.
The packing presser 140 is fixed to the housing 110 so that the packing 1 accommodated in the packing box 130 is pressed in the axial direction.
That is, the packing 1 is used in a state where it is sandwiched between the packing presser 140 and the ring plane 110b and compressed in the axial direction.
The packing 1 is accommodated in the packing box 130 in such a manner that the size is increased inward in the radial direction and outward in the radial direction of the rotating shaft 120 by being compressed.

In the present embodiment, since the rotary shaft 120 exists inside the packing 1 and the inner wall surface of the packing box 130 exists outside, the deformation of the packing 1 in the packing box is regulated by these. become.
And the packing 1 of this embodiment used as a gland packing functions as the contact pressure with respect to the inner wall surface of the rotating shaft 120 or the packing box 130 by the repulsive force with respect to this regulation, and exhibits the outstanding sealing performance.
More specifically, the packing 1 of the present embodiment has a low compressive force received from the packing presser 140 by the low concentration region 10t because the low concentration region 10t having a low filler concentration is disposed on the back side of the first surface 10a. The pressure can be favorably converted to a pressure directed in the direction, and a large contact pressure can be generated on the first surface 10a.
The first surface 10a is in sliding contact with the outer peripheral surface of the rotating shaft 120 when the rotating shaft 120 rotates. In the packing 1 of the present embodiment, the first surface 10a is in contact with the sliding contact surface with the rotating shaft 120. The first surface 10a is formed of a polyurethane elastic body containing a thermosetting polyurethane and a filler, and the first surface 10a is composed of the high-concentration region 10s. The slipperiness is exerted on the sliding contact surface.
Therefore, in the packing 1 of this embodiment, it is possible to achieve both excellent wear resistance and excellent sealing properties.

It does not specifically limit as said thermosetting polyurethane which comprises the packing 1 in this embodiment, The thing obtained by reaction of a polyol and polyisocyanate is employable.
Moreover, as the filler, an inorganic filler or an organic filler can be employed.

Examples of the inorganic filler include inorganic oxide particles made of inorganic oxides such as cerium oxide, zirconium oxide, zinc oxide, aluminum oxide, iron oxide, and silicon oxide; inorganic hydroxide particles such as aluminum hydroxide and magnesium hydroxide ; Inorganic carbonate particles such as calcium carbonate and magnesium carbonate; inorganic nitride particles such as boron nitride, aluminum nitride and titanium nitride; inorganic carbide particles such as silicon carbide and titanium carbide; silicic acid such as talc, clay, mica and montmorillonite Salt mineral particles; metal powders made of metals such as copper, nickel, iron and aluminum; graphite particles; glass particles; fly ash and the like.
The inorganic filler may be solid or hollow.
Therefore, inorganic balloons such as glass balloons and fly ash balloons may be employed as inorganic fillers to be included in the elastic member of this embodiment.
The inorganic filler may be a short fiber called chopped fiber or the like.
Accordingly, short fibers such as glass fiber, carbon fiber, rock wool, and steel wool may be employed as the inorganic filler to be included in the elastic member of the present embodiment.

Examples of the organic filler include particles formed of a resin having a higher hardness than thermosetting polyurethane.
Examples of the resin include polyolefin resins such as polyethylene resin and polypropylene resin; polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin; aliphatic polyamide resins such as polyamide 6, polyamide 66, polyamide 11, and polyamide 12; p-phenylenediamine -Aromatic polyamide resin such as terephthalic acid copolymer resin, m-phenylenediamine-isophthalic acid copolymer resin; polyimide resin; polytetrafluoroethylene resin, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer resin, tetrafluoro Ethylene-hexafluoropropylene copolymer resin, tetrafluoroethylene-ethylene copolymer resin, polyvinylidene fluoride resin, polychlorotrifluoroethylene resin Chlorotrifluoroethylene ethylene - fluororesin such as ethylene copolymer resins, polyvinyl chloride resins, poly vinylidene chloride resins; polycarbonate resins, acrylic resins, polystyrene resins; polyurethane resins.
The organic filler may be solid or hollow.
The organic filler may be a short fiber.

The inorganic filler and the organic filler may be used alone or in combination of two or more.
Moreover, you may make the polyurethane elastic body which comprises the elastic member of this embodiment contain both an inorganic filler and an organic filler.

Among these fillers, it is suitable for being unevenly distributed on the first surface side in the polyurethane elastic body of the present embodiment, and also has good adhesion to thermosetting polyurethane, so that inorganic oxide particles and inorganic particles can be used. A balloon is preferred.
In particular, cerium oxide particles, zirconium oxide particles, and the like are preferable because they are easily compatible with thermosetting polyurethane, have excellent chemical stability, and are suitable for reducing sliding resistance.
The cerium oxide particles and the like are also suitable in that they are likely to be unevenly distributed on the sliding surface side of the elastic member because the specific gravity is sufficiently heavier than that of the thermosetting polyurethane.

What is necessary is just to select suitably content of the filler in a polyurethane elastic body according to the kind and use of packing.
As the filler in the present embodiment, an inorganic filler is suitable.
The filler content in the polyurethane elastic body is usually 0.1 to 20 parts by mass with respect to 100 parts by mass of the thermosetting polyurethane contained in the polyurethane elastic body.
When the filler is a high-density inorganic filler (high-density inorganic filler) having a density of 5.0 g / cm ³ or more such as cerium oxide particles or zirconium oxide particles, the filler content relative to 100 parts by mass of the thermosetting polyurethane Is preferably 2 to 20 parts by mass.
By setting the content of the high-density inorganic filler to 2 parts by mass or more, the polyurethane elastic body can remarkably exhibit the effect of reducing sliding resistance.
On the other hand, by setting the content of the high-density inorganic filler to 20 parts by mass or less, the polyurethane elastic body can be made excellent in flexibility, and the sealing performance excellent in the packing of this embodiment can be exhibited. .
The content of the high-density inorganic filler is more preferably 3 to 15 parts by mass with respect to 100 parts by mass of the thermosetting polyurethane in order to exhibit the above effects more reliably.

When the filler is a low density inorganic filler (low density inorganic filler) having a density of 1.0 g / cm ³ or less like an inorganic balloon, the filler content relative to 100 parts by mass of the thermosetting polyurethane is 0.1. It is preferable that it is -2.0 mass parts.
By setting the content of the low-density inorganic filler to 0.1 part by mass or more, the polyurethane elastic body can remarkably exhibit the effect of reducing sliding resistance.
On the other hand, by setting the content of the low density inorganic filler to 2 parts by mass or less, the polyurethane elastic body can be made excellent in flexibility, and the sealing performance excellent in the packing of the present embodiment can be exhibited.
The content of the low density inorganic filler is more preferably 0.2 to 1.0 part by mass with respect to 100 parts by mass of the thermosetting polyurethane in order to exhibit the above effect more reliably.

The average particle diameter of the filler is preferably 0.5 to 100 μm.
The average particle diameter is preferably 0.5 to 10 μm when the filler is inorganic oxide particles, and preferably 20 to 80 μm when the filler is an inorganic balloon.
When the particle size of the filler is a certain value or more, the specific surface area can be suppressed to a certain value or less, the flow resistance when dispersed in the thermosetting polyurethane can be suppressed, and it becomes easy to be unevenly distributed in the polyurethane elastic body. .
On the other hand, when the particle size of the filler is not more than a certain value, it is possible to suppress the filler from falling off the sliding contact surface, and it is possible to continuously maintain a low sliding resistance against the packing over a long period of time.
In addition, an average particle diameter is a median diameter (value (d50) at the time of cumulative particle size distribution 50%) on the volume basis using a laser diffraction type particle size distribution measuring apparatus (for example, LMS-2000e manufactured by Seishin Enterprise Co., Ltd.). Desired.
In the packing according to this embodiment, such fillers are unevenly distributed in the thickness direction.
A technique for unevenly distributing the filler will be described later.

The thermosetting polyurethane in this embodiment contains a polyol component, an isocyanate component, a crosslinking agent, and the like.
It does not specifically limit as said polyol component, For example, polyester polyol, polyether polyol, polycaprolactone polyol etc. are mentioned.
The polyol preferably has a number average molecular weight of 1000 to 3000.
The number average molecular weight is a measured value in terms of polystyrene by GPC (gel permeation chromatograph) measurement.

Examples of the polyester polyol include those obtained by reacting dicarboxylic acid and glycol according to a conventional method.
Examples of the dicarboxylic acid include aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid, aliphatic dicarboxylic acids such as adipic acid, succinic acid, azelaic acid, and sebacic acid, and oxybenzoic acid. These oxycarboxylic acids, their ester-forming derivatives, and the like.
Among these, adipic acid is preferable because it is advantageous for forming a polyurethane elastic body having good wear resistance.

Examples of the glycol include aliphatic glycols such as ethylene glycol, 1,4-butanediol, diethylene glycol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,9-nonanediol, and triethylene glycol; Examples include alicyclic glycols such as 1,4-cyclohexanedimethanol; aromatic diols such as p-xylene diol; polyoxyalkylene glycols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.
As the glycol, aliphatic glycol is preferable, and ethylene glycol and 1,4-butanediol are more preferable.
The polyester polyol, which is a reaction product of dicarboxylic acid and glycol, has a linear structure, but a branched structure using a trivalent or higher valent ester-forming component may be used for a part or all thereof.

Examples of the polyether polyol include polyalkylene glycols such as polyethylene glycol, polypropylene glycol, polytetramethylene glycol, and copolymers thereof.
Among these, polytetramethylene glycol is preferable because it is advantageous for forming a polyurethane elastic body having good wear resistance.
Examples of the polycaprolactone polyol include those obtained by ring-opening addition of ε-caprolactone using a low molecular weight glycol as an initiator in the presence of a catalyst.

These polyol components may be used alone or in combination of two kinds.
The polyol component is preferably polyethylene adipate ester polyol (PEA). In this case, the chemical resistance excellent in packing can be exhibited.
Therefore, the packing in which the sliding contact surface is formed of the polyurethane elastic body containing the polyol component as described above can suppress a decrease in wear resistance due to swelling or the like.

It does not specifically limit as said polyisocyanate, For example, aliphatic isocyanate, alicyclic isocyanate, aromatic isocyanate etc. are mentioned. Of these, aromatic isocyanates are preferred from the viewpoint of good wear resistance.
Examples of the aliphatic isocyanate include 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, and lysine diisocyanate. In addition, isocyanurate bodies, biuret bodies and modified adduct bodies of hexamethylene diisocyanate and isophorone diisocyanate are also included.
Examples of the alicyclic isocyanate include alicyclic diisocyanates such as isophorone diisocyanate (IPDI), 4,4′-dicyclohexylmethane diisocyanate, 1,4-cyclohexane diisocyanate, and norbornane diisocyanate (NBDI).
Examples of the aromatic isocyanate include tolylene diisocyanate (TDI), phenylene diisocyanate, 4,4′-diphenylmethane diisocyanate (MDI), 1,5-naphthalene diisocyanate, xylylene diisocyanate (XDI), carbodiimide-modified MDI, and urethane. Examples include modified MDI.
The said polyisocyanate may be used independently and may use 2 or more types together.

Examples of the crosslinking agent include ethylene glycol, propylene glycol, butanediol, hexanediol, diethylene glycol, trimethylolpropane, glycerin, hydrazine, ethylenediamine, diethylenetriamine, 4,4′-diaminodiphenylmethane, 4,4′-diaminodicyclohexylmethane. N, N-bis (2-hydroxypropyl) aniline, water and the like.
Of these, butanediol and trimethylolpropane are preferred because they are advantageous for forming a polyurethane elastic body having good oil resistance.
The said crosslinking agent may be used independently and may be used together 2 or more types.

  The polyurethane elastic body includes, as components other than the above, for example, chain extenders, reaction aids such as crosslinking accelerators and crosslinking retarders, hydrolysis inhibitors, colorants, light stabilizers, heat stabilizers, antioxidants, You may contain an antifungal agent, a flame retardant, etc.

In the packing 1 of the present embodiment, the filler is unevenly distributed so that a concentration gradient is generated in the thickness direction toward the first surface 1a that is a slidable contact surface with the rotating shaft 120.
The polyurethane elastic body having such a structure can be produced by, for example, the following first method, second method, and the like.

(First method)
A liquid raw material composition containing a component (polyol, polyisocyanate, etc.) that becomes polyurethane by a thermosetting reaction and a filler in a predetermined ratio is prepared.
Next, the obtained raw material composition is put into a centrifugal molding machine and thermally cured under predetermined conditions to produce a cylindrical polyurethane elastic body.
Thereafter, the polyurethane elastic body is cut into a string having a predetermined width to obtain the packing (elastic member).

In the first method, the filler can be unevenly distributed in the thickness direction by utilizing the specific gravity difference with the thermosetting polyurethane.
That is, in this method, a liquid composition containing a filler having a specific gravity different from that of thermosetting polyurethane and thermosetting to become a polyurethane elastic body is prepared, and directed toward the thickness direction of the polyurethane elastic body to be produced. A polyurethane elastic body in which a high-concentration region and a low-concentration region are arranged in the thickness direction is produced by applying a centrifugal force to thermally cure the composition.

In the first method, when a filler having a specific gravity higher than that of thermosetting polyurethane (for example, cerium oxide particles) is blended, a polyurethane elastic body in which the filler is unevenly distributed on the mold surface side of the mold is produced.
In this method, the polyurethane elastic body is usually produced so that the surface in contact with the mold of the centrifugal molding machine becomes the first surface 10a.
On the other hand, when a filler having a specific gravity lower than that of thermosetting polyurethane (for example, inorganic balloon) is blended, polyurethane elasticity in which the filler is unevenly distributed on the side opposite to the mold surface of the mold (hereinafter also referred to as the air side). The body can be made.
In this method, the polyurethane elastic body is usually produced so that the surface in contact with the mold of the centrifugal molding machine becomes the second surface 10b.
Further, when both fillers are blended, a polyurethane elastic body having a low concentration region 10t at the center in the thickness direction and high concentration regions 10s on both surface sides of the first surface 10a and the second surface 10b is produced. can do.

(Second method)
A raw material composition (composition A) containing a filler is prepared in the same manner as in the first method.
Moreover, a raw material composition (composition B) having a filler content lower than that of the composition A is separately prepared. The composition B may not contain a filler.
Next, any one of the obtained composition A and composition B is put into a centrifugal molding machine and reacted under a predetermined condition to be in a semi-cured state.
Subsequently, the other composition that has not been charged is charged into a centrifugal molding machine and cured under a predetermined condition to produce a cylindrical polyurethane elastic body.
Thereafter, the polyurethane elastic body is cut into a string having a predetermined width to obtain the packing (elastic member).

In this second method, the filler can be unevenly distributed even when the specific gravity difference between the thermosetting polyurethane and the filler is small.
In the second method, when a filler having a specific gravity higher than that of the thermosetting polyurethane is blended, the composition A is introduced first.
On the other hand, when a filler having a specific gravity lower than that of the thermosetting polyurethane is blended, the composition B is introduced first.
Thereby, the polyurethane elastic body in which the filler is unevenly distributed on either the mold surface side or the air side can be produced.

  In the above method, a laminated structure of two or more layers including a first polyurethane elastic body layer constituting the sliding contact surface and a second polyurethane elastic body layer in contact with the first polyurethane elastic body layer from the back side is provided. When the filler concentration of the first polyurethane elastic layer is X mass%, the second polyurethane elastic layer is formed so that the filler concentration is 0 mass% or more and less than X mass%. The polyurethane elastic body in which the low concentration region is constituted by the second polyurethane elastic body layer can be produced.

In these methods, the uneven distribution state of the filler can be adjusted by adjusting the molding temperature (curing time), the rotational speed of the molding machine, and the like.
In these first and second methods, the composition before being charged into the molding machine may contain a polyol component and an isocyanate component unreacted, or a state in which both have reacted to some extent (prepolymer). ).
That is, the thermosetting reaction for forming the polyurethane elastic body may be performed by a one-shot method or a prepolymer method.

The hardness (JIS A hardness) on the surface opposite to the sliding contact surface of the polyurethane elastic body is preferably 55 to 90 °, and more preferably 65 to 80 °.
The JIS A hardness is a value measured by a spring type A hardness tester according to JIS K 7312.
Further, the polyurethane elastic body preferably has a rebound resilience of 20% to 40% in order to suppress the generation of abnormal noise (buzzing sound) at the time of sliding contact with the rotating shaft, and the rebound resilience is 10% More preferably, it is -50%.
The impact resilience means a value measured in accordance with JIS K 7312.

By having such mechanical characteristics, the polyurethane elastic body can be used as a gland packing excellent in wear resistance.
In addition, the packing in this embodiment does not need that the elastic member is formed only with a polyurethane elastic body, and may have an elastic member in which another elastic body and a polyurethane elastic body are combined.
Moreover, the packing in this embodiment does not need to be formed only with an elastic member, and may be a combination of an elastic member and another member.

(Second Embodiment)
Next, an embodiment different from the gland packing described above will be described.
The packing according to the second embodiment is used as a seal for a container with a lid.
The packing according to the second embodiment will be described below with reference to FIGS.
That is, in the present embodiment, a method of using the packing 1 ′ will be described by taking the bottle container 200 as an example of a container with a lid.

The bottle container 200 includes a container main body 210 for storing the contents and a screw cap 220.
The container main body 210 includes a storage portion 210a that stores a storage object, and an opening 210b for taking the storage material into and out of the storage portion.
The opening 210b extends in a cylindrical shape vertically upward from the upper end of the housing portion 210a and has a circular opening at the tip.

The screw cap 220 is configured to be fitted to the opening 210b of the container main body 210 from above, and is configured to be fitted to the opening 210b.
The screw cap 220 includes a disk-shaped ceiling 220 a for opening and closing the opening 210 b of the container body 210 and a side wall 220 b extending downward from the outer periphery of the ceiling 220.
The ceiling 220a has a disk shape that is slightly larger than the opening so as to close the circular opening at the tip of the opening 210b.
Accordingly, the side wall 220b is formed in a cylindrical shape having an inner diameter that is slightly larger than the opening 210b of the container body 210, and is provided below the ceiling 220a.
In this embodiment, a screw is provided on each of the inner peripheral surface of the side wall 220b and the outer peripheral surface of the opening 210b so that the screw cap 220 can be attached to and detached from the container body 210 by screwing.

As shown in FIG. 3, the packing 1 ′ of the present embodiment has a ring shape corresponding to the tip shape of the opening 210 b of the container body 210, and is a cross-sectional shape when cut along a plane orthogonal to the circumferential direction. Is a horizontally long rectangle as shown in FIG.
The packing 1 ′ in the second embodiment is common to the packing in the first embodiment in that it is formed by only the polyurethane elastic body 10 ′.
The polyurethane elastic body 1 ′ constituting the packing 1 ′ has a first surface 10 a ′ and a second surface 10 b ′ that face each other in the thickness direction T.
And the packing 1 'in 2nd Embodiment and the packing 1 in 1st Embodiment are common also in the point by which 1st surface 10a' of this polyurethane elastic body 1 'is utilized as a sliding contact surface.

The packing 1 ′ in the present embodiment is formed by the second method described above, and has a multilayer structure laminated in the thickness direction.
That is, the polyurethane elastic body 10 ′ includes a first polyurethane elastic body layer L1 that constitutes the sliding contact surface, and a second polyurethane elastic body layer L2 that contacts the first polyurethane elastic body layer L1 from the back side. When having a laminated structure of two or more layers and the filler concentration of the first polyurethane elastic body layer L1 is X mass%, the second polyurethane elastic body layer L2 has a filler concentration of 0 mass% or more and less than X mass%. The low-concentration region 10t ′ is constituted by the second polyurethane elastic layer L2.

Specifically, the packing 1 ′ in the present embodiment has a two-layer structure, the first surface 10a ′ is formed of the first polyurethane elastic body layer L1, and the second surface 10b ′ is the first. 2 polyurethane elastic layer L2.
The first polyurethane elastic body layer L1 in the present embodiment includes a filler at a ratio of 0.1 to 20 parts by mass with respect to 100 parts by mass of the thermosetting polyurethane, and the second polyurethane elastic body layer L2 includes a filler. Is not included at all.
That is, in this embodiment, the low concentration region 10t ′ does not contain any filler.

The packing 1 ′ of the present embodiment is greatly different in slipperiness between the first surface 10 a ′ and the second surface 10 b ′, and the first surface 10 a ′ has a lower coefficient of friction than the second surface 10 b ′. ing.
Further, the packing 1 ′ of the present embodiment has a lower hardness on the second surface side than on the first surface side.
This difference in slipperiness and hardness can be confirmed by finger touch, but the packing 1 ′ of the present embodiment has a small area on the first surface 10a ′ and the second surface 10b ′, so that the tactile sensation causes these differences. May be difficult to distinguish.
Accordingly, in the packing 1 ′ of the present embodiment, the first polyurethane elastic body layer L1 and the second polyurethane elastic body layer L2 have different shades so that the first surface 10a ′ and the second surface 10b ′ have different color tones. .
Specifically, the packing 1 ′ of the present embodiment has a color tone between the first surface 10 a ′ and the second surface 10 b ′ expressed in the L ^* , a ^* , b ^* color system. The first surface 10a ′ and the second surface 10b ′ are color-coded so that a color difference (ΔE ^* ) of 0.5 or more is generated.
In order to make the first surface 10a ′ and the second surface 10b ′ easier to distinguish, it is more preferable to provide a color difference of 2 or more, and it is more preferable to provide a color difference of 5 or more.

The screw cap 220 includes a plurality of minute protrusions 220c extending downward on the lower surface side of the ceiling part 220a, and the protrusions are arranged side by side on the same circumference. Is provided.
The protruding piece 220c is formed such that when the screw cap 220 is attached to the bottle container 200, the tip (lower end) of the protruding piece 220c reaches slightly downward from the opening of the container body 210, The circumference is arranged so as to be inside the opening edge of the container body 210.
The distance from the protruding piece 220c to the inner peripheral surface of the side wall 220b is slightly smaller than the dimension in the radial direction of the packing 1 ′ of the present embodiment.
The packing 1 ′ is disposed in a form that is press-fitted into an annular region between the protruding piece 220 c and the inner peripheral surface of the side wall portion 220 b.
The packing 1 ′ is arranged such that the outer peripheral surface is in contact with the side wall portion 220 b and the inner peripheral surface is in contact with the protruding piece 220 c, and the first surface 10 a ′ is in contact with the ceiling portion 220 a. It is arranged in a state.
That is, the packing 1 ′ is interposed between the opening 210 a of the container body 210 and the screw cap 220 and used for sealing the bottle container 200.
The contact area between the tip of the opening 210a and the packing is smaller than the contact area between the ceiling 220a of the screw cap 220 and the packing.
The packing 1 ′ of the present embodiment is constituted by a second polyurethane elastic layer L <b> 2 whose side abutting against the opening 210 a is relatively low in hardness and easily deformable compared to the first polyurethane elastic layer L <b> 1. Therefore, the bottle container 200 can exhibit excellent sealing performance.

When the bottle container 200 is opened and closed, the opening 210a and the screw cap 220 are relatively rotated, so that the packing 1 'is in sliding contact with at least one of them.
The packing 1 ′ of the present embodiment has excellent sliding properties with the screw cap 220 when the bottle container 200 is opened and closed because the first surface 10 a ′ is in contact with the ceiling part 220 a, and is temporarily screwed Even when abrasion powder is generated by sliding contact with the cap 220, the abrasion powder is unlikely to fall into the container body.
Further, in the packing 1 ′ of the present embodiment, on the back side in the press-fitting direction to the screw cap 220, the side pressure applied from the side wall part 220 b and the projecting piece 220 c is higher than that on the near side, but this back side is the first polyurethane elastic. By forming the high concentration region 10s ′ by the body layer L1, good sliding properties are exhibited even in sliding contact with the side wall portion 220b and the protruding piece 220c.
Further, the packing 1 ′ of the present embodiment can be easily discriminated whether or not it is correctly attached in the state where it is attached to the screw cap 220 because the first surface 10a ′ and the second surface 10b ′ are color-coded. .

When the packing 1 ′ of the present embodiment is to have a higher slidability with the tip of the opening 210 a than with the screw cap 220, the second surface 10 b ′ contacts the ceiling 220 a. The first surface 10a ′ may be disposed so as to be in contact with the opening 220a.
In this case, since the back side in the press-fitting direction is the low concentration region 10t ′, a frictional force is easily exerted between the side wall portion 220b and the projecting piece 220c, and the packing is prevented from inadvertently dropping from the screw cap 220. be able to.

As described above, the packing 1 ′ according to the second embodiment exhibits excellent wear resistance on the sliding contact surface in the same manner as the packing 1 of the first embodiment.
And packing 1 'concerning 2nd Embodiment is the same as packing 1 of 1st Embodiment also in the point which exhibits the outstanding sealing performance by having low concentration area | region 10t'.
In addition, the packing of this invention is not limited to the illustration in this 2nd Embodiment, and the illustration in the above-mentioned 1st Embodiment at all.

  1, 1 ': Packing, 10, 10': Elastic member, 10a, 10a ': First surface (sliding contact surface), 10s, 10s': High concentration region, 10t, 10t': Low concentration region

Claims (5)

A packing provided with an elastic member,
The elastic member includes a sliding contact surface that is in sliding contact with the mating member,
At least the sliding contact surface is formed by a polyurethane elastic body containing a thermosetting polyurethane and a filler,
The polyurethane elastic body is a packing in which a low concentration region having a filler concentration lower than the concentration of the filler on the sliding contact surface is provided on the back side of the sliding contact surface. The polyurethane elastic body is provided with a concentration gradient of the filler so that the concentration of the filler increases toward the sliding contact surface,
The packing according to claim 1, wherein the low concentration region is provided on the back side of the sliding contact surface by providing the concentration gradient. The polyurethane elastic body has a laminated structure of two or more layers including a first polyurethane elastic body layer constituting the sliding contact surface and a second polyurethane elastic body layer in contact with the first polyurethane elastic body layer from the back side. Have
When the filler concentration of the first polyurethane elastic layer is X mass%, the second polyurethane elastic layer is formed such that the filler concentration is 0 mass% or more and less than X mass%,
The packing according to claim 1, wherein the low-concentration region is constituted by the second polyurethane elastic body layer.   4. A gland packing that is arranged so as to cover the rotating shaft of the rotating body and is compressed in the axial direction of the rotating shaft, and is used with the sliding contact surface in sliding contact with the rotating shaft. The packing according to any one of the above. It is used for a container with a lid having a container body having a cylindrical opening, and a screw cap fitted to the opening.
The packing according to any one of claims 1 to 3, wherein the packing is interposed between the opening of the container body and the screw cap and used for sealing the container with a lid.