JP2019090726A - Method for measuring cure degree of silicone rubber composition - Google Patents

Abstract

To provide a method for measuring the cure degree of a silicone rubber composition with which it is possible to accurately and easily measure the cure degree of a silicone rubber composition.SOLUTION: Provided is a method for measuring the cure degree of a silicone rubber composition. The method for measuring the cure degree of a silicone rubber composition includes: filling a cylindrical container, having one end closed by a lid, with the silicone rubber composition; curing the other end side of the silicone rubber composition that is opposite the one end side and removing the lid; inserting a rod-like tip piece into the silicone rubber composition from the one end side, and measuring a repulsive force that the tip piece has received, for each inserted length of the tip piece.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method of measuring the degree of curing of a silicone rubber composition.

  Heretofore, a silicone rubber-based resin having a fixed shape and plasticity before curing is used in various fields. For example, silicone rubber having the above-mentioned properties is used for covering a part of a structure or for sealing joints of members of a structure.

  As a technique as described above, for example, in Patent Document 1, an uncured reactive bonding type silicone rubber material is previously shaped into a triangular rod, and a release film is formed on the surface facing at least one apex angle. A stuck silicone rubber sealant is disclosed. This silicone rubber sealing material can be used to seal the triangular seal portion formed by the floor surface and the wall surface of the structure. Here, as the uncured silicone rubber, silicone rubber which is cured by condensation polymerization is used.

Japanese Patent Application Laid-Open No. 11-92746

The silicone rubber which is cured by condensation polymerization is allowed to stand in the air, and is cured sequentially from the surface facing the air to the inside not facing the air by moisture in the air. When installing a member using a silicone rubber composition, under which conditions the curing to which site is related to the time required for installation or the time that can be performed. Therefore, such curing information affects the workability in installation.
That is, with respect to the silicone rubber composition which is a raw material of these members, when a sample of the silicone rubber composition having a certain volume or shape is allowed to stand for a certain period of time at a certain temperature and humidity under certain conditions, for example It is effective to measure the degree of curing of which part of the inner side cures.

As a method of measuring the curing degree of the silicone rubber composition, for example, a silicone rubber composition is filled in a test tube, and the silicone rubber composition is cured on the side exposed to the air on the mouth side of the test tube. The silicone rubber composition can be visually observed from the side surface of the silicone rubber composition, and the thickness (volume) of the cured portion of the silicone rubber composition can be measured by visual observation (resin test tube method). However, according to this measurement method, since it is measurement by eye measurement, it is difficult to accurately measure the cured volume of silicone rubber, the accuracy of the measurement method is not sufficient, and an error occurs every time measurement is performed. It is also difficult to compare the test results under the same conditions.
A method is also conceivable in which a partially cured silicone rubber composition is separated into test pieces for each part and measurement of physical properties or chemical analysis is performed, but such measurement can not be easily performed. .
In this field, there is a need for a method of accurately and easily measuring the degree of cure of silicone rubber compositions.

  The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a method of measuring the curing degree of a silicone rubber composition which can measure the curing degree of the silicone rubber composition accurately and easily. I assume.

The present invention which solves the above-mentioned subject has the following modes.
<1> A method for measuring the degree of cure of a silicone rubber composition, comprising: filling a container with the silicone rubber composition; curing at least a part of one end side of the silicone rubber composition; A rod-like repulsive force measuring means is inserted toward the cured part from the other end opposite to the cured one end side, and the repulsive force measuring means is for each length in which the repulsive force measuring means is inserted. A method of measuring the degree of curing of a silicone rubber composition, which measures the repulsive force received.
<2> The container has a cylindrical shape in which at least one end can be airtightly closed by a lid, and when the container is cured, one end of the container to be cured is opened, and the other end is a lid When the reaction force measuring means is inserted, the lid on the other end side is removed, and the reaction force measuring means is inserted from the other end side to the silicone rubber composition, <1 Method of measuring degree of cure of silicone rubber composition of>.
<3> The method for measuring the degree of cure of a silicone rubber composition according to <1> or <2>, wherein the silicone rubber composition contains a polyorganosiloxane and a crosslinking agent.
<4> The method for measuring the degree of cure of a silicone rubber composition according to any one of <1> to <3>, wherein the length of the repulsive force measurement means is 10 to 40 mm and the diameter is 1 to 2.5 mm.
<5> The method for measuring the degree of cure of a silicone rubber composition according to any one of <1> to <4>, wherein the insertion of the reaction force measurement means is performed by a load tester at a moving speed of 1 to 10 mm / min.
<6> The degree of curing of the silicone rubber composition according to any one of <1> to <5>, wherein the container has a lid that can be screwed to both ends, and can be airtightly sealed by the lid. Method.
<7> The container according to any one of <2> to <6>, wherein the cylindrical length is 5 to 40 mm and the cylindrical cross-sectional area is 75 to 750 mm ² with respect to the inner surface shape of the container. Method of measuring degree of cure of silicone rubber composition.

  According to the present invention, it is possible to obtain a method of measuring the degree of cure of a silicone rubber composition that can measure the degree of cure of the silicone rubber composition accurately and easily.

It is the schematic which shows the measuring method of the curing degree of the silicone rubber composition of this embodiment. It is the schematic which shows the measuring method of the curing degree of the silicone rubber composition of this embodiment. It is a graph which shows the measurement result of the hardening degree of a present Example.

  Hereinafter, the method of measuring the degree of cure of the silicone rubber composition of the present invention will be described by showing an embodiment. However, the present invention is not limited to the following embodiments.

[Embodiment]
In the method of measuring the degree of cure of the silicone rubber composition of the present embodiment, the silicone rubber composition for which the degree of cure is measured is preferably a silicone rubber composition having formability and plasticity.
The term “formability” refers to the property that the shape is held constant unless an external force is applied. For example, there is no liquidity. Having plasticity means that the shape can be changed by an external force. More specifically, the external force may be a force that can be pressed by a finger. In addition, in this embodiment, although a silicone rubber composition hardens by various reactions after use (after installation) so that it may mention later, it points out that it has formality and plasticity before hardening.

  More specifically, having plasticity is preferably such that the silicone rubber composition has a plasticity in the range of 100 to 200 measured at 25 ° C. before curing by a parallel plate plasticity meter. The plasticity is more preferably in the range of 100 to 180, still more preferably in the range of 120 to 160, and particularly preferably in the range of 130 to 150. In this embodiment, the degree of plasticity measured by a parallel plate plasticity meter refers particularly to the initial Williams plasticity measured by a Williams plasticity meter based on JIS K 6249. However, the silicone rubber composition to be measured has a spherical shape of 2 g. And When the plasticity is 100 or more, the silicone rubber composition has formability in an uncured state. If the plasticity of the silicone rubber composition does not exceed 200, the silicone rubber composition can be freely deformed in installation.

  In addition, the tackiness of the silicone rubber composition is a tackiness test based on the ball-turning method of JIS Z 0237, that is, a ball number is 3 to 3 when measured at a ball tilt angle of 30 ° by a tilting ball tack test. The range of 7 is preferable. When the tackiness of the silicone rubber composition is in this range, it can be used by sticking to a structure or the like when it is installed.

  The basic composition of the silicone rubber composition of the present embodiment is preferably a silicone rubber that cures by condensation reaction. By using a silicone rubber composition that cures by a condensation reaction, a silicone rubber composition having the above-described appropriate shape and plasticity can be obtained. The above condensation reaction is preferably a reaction initiated by contact of the silicone rubber composition prior to curing with air or moisture. As such a condensation reaction, for example, a condensation reaction of polyorganosiloxane can be used. In the present embodiment, as the resin to be cured by the condensation reaction, one containing the following polyorganosiloxane, a crosslinking agent, a curing catalyst, a filler, and an adhesion imparting component is used.

(Polyorganosiloxane)
The polyorganosiloxane in the present embodiment is a main component of the silicone rubber composition, and it is preferable to use a diorganosiloxane represented by the following chemical formula (1) or (2).

（式中、Ｒはそれぞれ独立して置換又は非置換の一価炭化水素基、Ｘはそれぞれ独立して酸素原子又は炭素数１〜８の二価炭化水素基、ｎは１以上の数である）

(Wherein R is each independently a substituted or unsubstituted monovalent hydrocarbon group, X is each independently an oxygen atom or a divalent hydrocarbon group having 1 to 8 carbon atoms, and n is a number of 1 or more) )

（式中、Ｙはそれぞれ独立して加水分解性基、Ｒはそれぞれ独立して置換又は非置換の一価炭化水素基、Ｘは酸素原子又は炭素数１〜８の二価炭化水素基、ｎは１以上の数である）

(Wherein, Y is each independently a hydrolyzable group, R is each independently a substituted or unsubstituted monovalent hydrocarbon group, X is an oxygen atom or a C 1 to C 8 divalent hydrocarbon group, n Is one or more numbers)

  Here, R in the above formulas (1) and (2) is an alkyl group such as methyl group, ethyl group, propyl group, butyl group, 2-ethylbutyl group or octyl group, or cycloalkyl group such as cyclohexyl group or cyclopentyl group Alkenyl group such as a group, vinyl group, propenyl group, butenyl group, heptenyl group, hexenyl group or allyl group, aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group or diphenyl group, benzyl group or phenyl group Aralkyl groups such as ethyl group, or chloromethyl group, trifluoropropyl group, 2-cyanoethyl group in which part or all of hydrogen atoms bonded to carbon atoms of these groups are substituted with halogen atoms, cyano group or the like And the same or different non-substituted or substituted ones selected from Ku 1 to 12 carbon atoms, in particular 1-10 monovalent hydrocarbon group.

In the above formulas (1) and (2), X is an oxygen atom or a divalent hydrocarbon group having 1 to 8 carbon atoms, and as the divalent hydrocarbon group,-(CH ₂ ) _m- (m is 1 to 8) What is represented by is preferable. Among these, oxygen atom and -CH ₂ CH ₂ -are more preferable.

Although n in the above formulas (1) and (2) is a number of 1 or more, it is preferably selected as follows. That is, although the viscosity of the diorganopolysiloxane in the formulas (1) and (2) is influenced by the n, the kinematic viscosity at 25 ° C. of the diorganopolysiloxane is 100 to 1,000,000 cs (mm ² / s ), Preferably 500 to 500,000 cs.

  Y in the above formula (2) is a hydrolyzable group. Specifically, an alkoxy group such as a methoxy group, an ethoxy group, a propoxy group or a butoxy group, a ketoxime group such as a dimethyl ketoxime group or a methylethyl ketoxime group, an acyloxy group such as an acetoxy group, or an isopropenyloxy group Alternatively, alkenyloxy groups such as isobutenyloxy group can be used.

Such diorganopolysiloxanes can be produced by known methods such as obtaining cyclic siloxanes or linear oligomers which are monomers of various organopolysiloxanes by an equilibrium reaction with an acid or a base catalyst. When a branched structure is introduced into the diorganopolysiloxane, the silane or siloxane containing SiO _3/2 units and / or SiO _4/2 units during the above-mentioned equilibration polymerization is at a level at which the diorganopolysiloxane does not gel. It is conventional to add. Furthermore, as for this diorganopolysiloxane, it is desirable to remove low molecular weight siloxane by stripping, washing or the like. When such an organosiloxane is used, the contamination in the initial stage of production and in the initial stage of use can be reduced.

(Crosslinking agent)
As the crosslinking agent, a silane having two or more, preferably three or more hydrolyzable groups in one molecule, or a partial hydrolysis condensate thereof can be used. The hydrolyzable group may be an alkoxy group such as methoxy group, ethoxy group or butoxy group, a ketoxime group such as dimethyl ketoxime group or methyl ethyl ketoxime group, an acyloxy group such as acetoxy group, an isopropenyloxy group or iso Examples include alkenyloxy groups such as butenyloxy group, amino groups such as N-butylamino group and N, N-diethylamino group, and amide groups such as N-methylacetamide group. Among these, an alkoxy group, a ketoxime group, an acyloxy group or an alkenyloxy group is preferable. The compounding amount of the crosslinking agent can be 1 to 50 parts, preferably 2 to 30 parts, and more preferably 5 to 20 parts based on 100 parts (parts by mass, the same shall apply hereinafter) of the diorganopolysiloxane. When the amount is 1 part by mass or more, appropriate formability can be obtained before curing, and suitable hardness and strength can be obtained after curing. By being 50 parts by mass or less, it is possible to obtain a certain degree of plasticity before curing, maintain appropriate elasticity even after curing, and obtain strength against cracking and the like.

(Curing catalyst)
Silicone rubber compositions can be accelerated to cure by using a curing catalyst. Examples of the curing catalyst include titanate esters such as tetraisopropoxytitanium, tetra n-butoxytitanium, tetrakis (2-ethylhexoxy) titanium, dipropoxybis (acetylacetona) titanium, or titanium isopropoxyoctylene glycol, or titanium chelates. Compound, zinc naphthenate, zinc stearate, zinc 2-ethyl octoate, iron 2-ethyl hexoate, cobalt 2-ethyl hexoate, manganese 2-ethyl hexoate, cobalt naphthenate, or Organometallic compounds such as alkoxyaluminum compounds, aminoalkyl substituted alkoxysilanes such as 3-aminopropyltriethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, hexylamine or phosphate acid Amine compounds such as silamine and salts thereof, quaternary ammonium salts such as benzyltriethylammonium acetate, lower fatty acid salts of alkali metals such as potassium acetate, sodium acetate or lithium borate, dialkyls such as dimethylhydroxylamine or diethylhydroxylamine Silanes or siloxanes containing a guanidyl group such as hydroxylamine or tetramethyl guanidyl propyl trimethoxysilane, tetramethyl guanidyl propyl methyl dimethoxysilane, or tetramethyl guanidyl propyl tris (trimethylsiloxy) silane can give. These are not limited to one type, and a mixture of two or more types may be used.

  The compounding amount of these curing catalysts may be 0 to 20 parts, preferably 0.001 to 10 parts, and more preferably 0.01 to 5 parts based on 100 parts of the diorganopolysiloxane. When the content is 0 parts by mass or more, a suitable fixed property can be obtained before curing, and a suitable hardness and strength can be obtained after curing. When the content is 20 parts by mass or less, a certain degree of plasticity can be obtained before curing, and appropriate elasticity is maintained even after curing, and strength against cracking and the like can be obtained.

(filler)
In the silicone rubber composition of the present embodiment, one or more fillers can be used for the purpose of reinforcement and the like in addition to the above components. As such a filler, for example, fumed silica, precipitated silica, silica obtained by hydrophobizing the surface of these silicas with an organosilicon compound, quartz powder, carbon black, talc, a reinforcing agent such as zeolite or bentonite, asbestos Examples thereof include fibrous fillers such as glass fibers, carbon fibers or organic fibers, or basic fillers such as calcium carbonate, zinc carbonate, zinc oxide, magnesium oxide, or celite.

  Among these fillers, silica, calcium carbonate, zeolite or the like is preferable, and in particular, fumed silica having a surface subjected to a hydrophobized treatment, or calcium carbonate is optimum. The compounding amount of the filler may be selected according to the purpose and the kind of the filler, but it is preferably 1 to 500 parts, particularly 5 to 100 parts with respect to 100 parts of the diorganopolysiloxane component of the above-mentioned base polymer. When the amount is 1 part by mass or more, appropriate formability can be obtained before curing, and suitable hardness and strength can be obtained after curing. By being 500 parts by mass or less, it is possible to obtain a certain degree of plasticity before curing, maintain appropriate elasticity even after curing, and obtain strength against cracking and the like.

(Adhesive component)
As an adhesion imparting component (adhesion promoter), amino group-containing organoalkoxysilanes such as γ-aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ-glycidoxypropyltrimethoxy Examples thereof include epoxy group-containing organoalkoxysilanes such as silane, mercapto-containing organoalkoxysilanes such as γ-mercaptopropyltrimethoxysilane, and reaction mixtures of amino group-containing organoalkoxysilanes and epoxy group-containing organoalkoxysilanes. The blending amount of this component is usually 0.1 to 5 parts by mass with respect to 100 parts by mass of the dipolyorganosiloxane component described above. When the amount is 0.1 parts by mass or more, appropriate formability can be obtained before curing, and suitable hardness and strength can be obtained after curing. In addition, good adhesion to the surface of a structure such as concrete can be easily obtained. When the amount is 5 parts by mass or less, a certain degree of plasticity can be obtained before curing, and appropriate elasticity is maintained even after curing, and strength against cracking and the like can be obtained.

(Physical properties after curing)
The silicone rubber composition preferably has a rubber hardness of 15 to 50 ° Hs in JIS A hardness after curing. When the rubber hardness is in the above range, it can be suitably used for protecting the surface of a structure.
The silicone rubber composition preferably has a tensile strength of 0.4 to 8.0 N / mm ² in JIS K6251 dumbbell shape No. 3 after curing. When the rubber hardness is in the above range, the surface of a structure such as concrete can be sufficiently protected.
The silicone rubber composition preferably has a tear strength of 1.0 to 18 N / mm according to JIS K6252 notched angled shape after curing. When the rubber hardness is in the above range, protection of a structure such as concrete can be sufficiently performed.

Preferably, the silicone rubber composition has an adhesion of 3.0 N or more to a mortar after curing. The adhesive strength is obtained by making the silicone rubber composition reinforced with a PET resin sheet 2 mm thick, 10 mm long and 120 mm in the ISO mortar which is a test mortar, and the silicone rubber composition on the side not reinforced with a PET resin sheet. It is the value to which the adhesive strength is measured with a tensile tester by sticking the substantially entire surface to the ISO mortar. When the silicone rubber composition is configured in this way, the silicone rubber composition adheres with sufficient strength when provided on the surface of a structure or the like. The upper limit of the adhesive strength is not particularly limited, but is preferably 100 N or less.
The method of measuring the degree of curing of the silicone rubber composition of the present embodiment is to place a part of the structure or adjacent to the structure, and a silicone rubber composition having physical properties suitable for its use before curing and after effect. It can be used suitably for things. For example, it is a silicone rubber composition composition for a concrete surface covering member. The silicone rubber composition having the above-described composition and physical properties can be suitably used as a silicone rubber composition for a concrete surface covering member.

(Method of measuring degree of cure of silicone rubber composition)
Next, specific steps of the method for measuring the degree of cure of the silicone rubber composition of the present embodiment will be described.

FIG. 1A is a partial side sectional view of a container 10 used in the method for measuring the degree of cure of a silicone rubber composition according to the present embodiment.
In the method of measuring the degree of cure of the silicone rubber composition of the present embodiment, the container 10 is filled with the silicone rubber composition 30. The silicone rubber composition 30 may be filled so as to fill the internal volume of the container or may be partially filled in the container, but the conditions for measurement, ie, the volume and thickness of the silicone rubber composition to be measured The amount to be filled is adjusted appropriately according to the length in the cylinder direction) and the like.
In the example shown in FIG. 1A, first, the cylindrical container 10 is prepared. The container 10 may be made of polyethylene, an acrylic resin, or a metal. By using the above-mentioned constituent material, it does not react with the silicone rubber composition which has the composition mentioned above, and it can maintain airtightness by screwing with lids 20A and 20B mentioned below. In the present embodiment, the container 10 is made of polyethylene.
The size of the container 10 can be appropriately selected depending on the nature of the silicone rubber composition to be measured and the scale to be measured (volume of the silicone rubber composition), but in the present embodiment, the length of the cylindrical internal space is 20 mm The tubular cross-sectional area is preferably 75 to 750 mm ² . When the space inside the container 10 is in the above-described range, the degree of curing with time can be appropriately measured for the silicone rubber composition having the above-described composition.
The shape of the container is selected from a cylindrical shape, and can be appropriately selected from a cylindrical shape, a polygonal cylindrical shape, and the like. In the present embodiment, the cylindrical container 10 is used because of the ease of filling with the silicone rubber composition and the ease of handling when closing the lid described later.

The container 10 is configured to be able to airtightly close at least one end by a lid. In the present embodiment, the container 10 has screw structures 11 at both ends, and by screwing the lids 20A and 20B, the both ends can be closed by the lids 20A and 20B. In the example shown, the screw structure 11 of the container 10 is a male screw.
In the present embodiment, the lids 20A and 20B are cylindrical with one end closed, and include the screw structure 11 of the container 10 and the screw structure 21 that can be screwed. In the example shown in the drawings, the screw structure 21 of the lids 20A and 20B is a female screw. When both of the lids 20A and 20B are screwed to the container 10 via the screw structure 21, the lids 20A and 20B can close the space between the lids 20A and 20B in an airtight state.

When measuring the degree of cure, at least a portion of one end side of the silicone rubber composition 30 is cured. In the present embodiment, as shown in FIG. 1B, one end to be cured is on the end 10 b side of the container 10, and the end 10 b side of the silicone rubber composition 30 is cured. First, the end 10a side which is the other end side of the container 10 opposite to the end 10b is closed by the lid 20A. The container 10 is then filled with the silicone rubber composition 30.
Next, the end 10 b side of the silicone rubber composition 30 is cured. Specifically, the container 10 is allowed to stand under conditions such as target temperature, humidity, curing time t and the like. The end 10b side of the container 10 may be opened without being closed by the lid 20B as shown in FIG. 1 (b). By not closing the end 10 b with the lid 20 B, the silicone rubber composition 30 touches the air and is cured from the end 10 b side by the moisture in the air. On the other hand, since the end 10a is closed by the lid 20A, the silicone rubber composition 30 near the end 10a does not touch the air and the moisture contained in the air, and the curing is delayed.
Alternatively, the lid 20B may be operated according to the conditions for curing the silicone rubber composition 30. For example, the end 10b side may be partially opened. As shown in FIG. 6C, the lid 20B may be closed in a non-airtight state, or the lid 20B may be airtightly closed in a state where the end 10b side of the container 10 contains air.
After curing the silicone rubber composition 30, as shown in FIG. 1 (d), the end 10b side of the silicone rubber composition 30 exposed to the atmosphere is cured and the volume is reduced due to the condensation reaction, A space is generated on the end 10 b side in the container.

  Next, an operation of inserting a rod-like repulsive force measuring means toward the cured part from the other end 10a opposite to the cured one end 10b of the silicone rubber composition 30 is performed. First, the lid 20A is removed from the container 10. In the example shown in FIG. 2A, the container 10 and the lid 20A are unscrewed to remove the lid 20A. In addition, the lid portion 20B is provided on the end 10b side so as to facilitate the subsequent operation, and the container 10 is upside down with respect to FIGS.

Then, the repulsive force measurement means is inserted into the silicone rubber composition 30 from the end 10a side (that is, the side where the lid 20A is provided during the above-mentioned curing and kept airtight). . Here, the repulsive force measuring means is a rod-like member which can be inserted into the silicone rubber composition 30 before curing, and is a means capable of measuring the repulsive force received from the silicone rubber composition 30 at the time of insertion. In the present embodiment, the repulsive force measuring means uses the tip terminal 40. The front terminal 40 is a rod-like member, and has a dimension such that the front terminal moving speed can be inserted under the condition of 1 to 10 mm / min with respect to the silicone rubber composition 30 before curing which has a certain degree of regularity. doing. As a specific example of a dimension, the tip terminal 40 has a length of 10 to 40 mm and a diameter of 1 to 2.5 mm.
In addition, the tip terminal 40 is configured to be able to detect the repulsive force F acting on the tip terminal 40 shown in FIG. 2B, as described later. For example, the front terminal 40 is provided as part of a device capable of detecting a repulsive force. In the present embodiment, the front terminal 40 is a tip portion of the load measuring device 41 of the load tester. The load measuring device 41 measures the repulsive force (N) at a moving speed of 1 to 10 mm / min. The tip portion may be made of metal or a resin that secures rigidity according thereto.
Further, the shape of the tip is preferably hemispherical, but may be triangular pyramid or truncated cone, and the shape having less friction to the silicone rubber composition is preferred.
In the example shown in FIG. 2B, the front terminal 40 is inserted substantially perpendicularly to the end 10 a side of the silicone rubber composition 30 in the direction D of displacement.

  Next, for each length (mm) in which the front terminal 40 is inserted into the silicone rubber composition 30, the repulsive force (N) received by the front terminal 40 is measured. In the example shown in FIG. 2 (b), the front terminal 40 is inserted to the silicone rubber composition 30 to the displacement length L, and the above-mentioned load testing machine repels the front terminal 40 for each displacement length L. Measure the repulsive force applied in the direction F of

  Here, when the silicone rubber composition 30 is cured as described above, it gradually cures from the end 10 b side exposed to the atmosphere toward the end 10 a side. Until the silicone rubber composition 30 is completely cured from the end 10 b side to the end 10 a side, the end 10 a side of the silicone rubber composition 30 is the softest and the end 10 b side is the most cured. Therefore, when the front terminal 40 is inserted into the silicone rubber composition 30 from the end 10a side to the end 10b side, the repulsion force received by the front terminal 40 increases as the length L of insertion displacement increases. Become. Therefore, for each portion of the silicone rubber composition 30, it is possible to obtain information on the degree of curing (the degree of curing) under certain conditions (certain temperature, humidity, curing time t). The measurement method of this embodiment can obtain measurement results with high accuracy and reproducibility by performing measurement under the same conditions. Further, since the repulsive force can be continuously measured for each inserted length L, continuous data can be obtained on the state of curing for each portion in the silicone rubber composition 30.

  Further, by combining information on a plurality of curing times t in which the silicone rubber composition 30 does not completely cure from the end 10a to the end 10b, it is possible to obtain information on the hourly curing of the silicone rubber composition 30, The information can be used for designing a member using the silicone rubber composition 30.

  Alternatively, the cured thickness L2 (mm / t) of each curing time t of the silicone rubber composition 30 under certain conditions may be determined as follows. Prior to the measurement, the front terminal 40 is pressed in a state where the silicone rubber composition 30 is completely cured, and the repulsive force to which the front terminal 40 is subjected is measured. For example, the front terminal 40 may be pressed against the silicone rubber composition 30 on the end 10 b side to measure the repulsive force. Next, the repulsive force (N) received by the front terminal 40 is measured while inserting the front terminal 40 to the end 10 a side of the silicone rubber composition 30 as described above, and the above-mentioned silicone rubber composition 30 is completely Continue to insert until it has the same value as the repulsive force in the cured state. The displacement length when the repulsive force becomes the same value is taken as a length L1 (not shown). The length L1 is the thickness of the uncured portion of the silicone rubber composition 30. A value obtained by subtracting the length L1 from the length L0 of the silicone rubber composition 30 in the container 10 is a thickness L2 (mm / t) at which the silicone rubber composition 30 is cured per curing time t.

  According to the method for measuring the degree of curing of the silicone rubber composition of the present embodiment, the silicone rubber composition is used without complicated equipment or operation other than the container and the means for measuring the repulsive force (the load tester in the present embodiment). Information on the degree of cure for each part of object 30 can be obtained. By measuring under the same conditions, highly accurate and repeatable measurement results can be obtained. Also, continuous data can be obtained on the state of curing for each part in the silicone rubber composition 30. From these effects, it is possible to provide a method of measuring the degree of cure of the silicone rubber composition that can accurately and easily measure the degree of cure of the silicone rubber composition.

  Hereinafter, the present embodiment will be described by way of examples, but the present invention is not limited to the following examples.

(Examples 1-5)
Silicone raw rubber mainly composed of organopolysiloxane having hydroxyl group at both ends of molecular chain: KE-76S (Shin-Etsu Chemical Co., Ltd., trade name, average polymerization degree 8,000) 100 parts by mass, fumed silica: Aerosil R Add appropriate amounts of-972 (trade name of Nippon Aerosil Co., Ltd.) and fumed silica with an average particle diameter of 15 μm, and 2 parts by mass of silicone oil having a hydroxyl group of 10 at both ends as a wetting agent. Was prepared to give a silicone rubber compound.
To each prepared silicone rubber compound, methyltrimethoxysilane as a crosslinking agent, tetrabutyl titanate, and dibutyltin laurate are appropriately added in an amount necessary for crosslinking, and thoroughly kneaded with two rolls, to obtain a silicone rubber composition 30 Was blended. In addition, the temperature at the time of compounding was 23 ° C., and the humidity was 7%.

One end 10a of a cylindrical container 10 made of polyethylene and having an inner diameter of φ15 (cross sectional area of about 356 mm ² ) and a length of 25 mm is closed with a lid 20A, and the container 10 is filled with the silicone rubber composition 30 approximately. It filled so that it might become 5 g and thickness 20 mm. Five containers 10 (Examples 1 to 5) were prepared.

For each example, it is allowed to stand at 23 ° C. and 50% humidity for the effect time t (0, 1, 2, 5, 14 days) shown in Table 1, and the end 10 b side of the silicone rubber composition 30 is cured I did.
For each example, after the time shown in Table 1, the lid 20A was removed, and the front terminal 40 was inserted from the end 10b side of the silicone rubber composition 30. The front terminal is a measuring device portion of a compact table-top load tester 1305 VC manufactured by Aiko Engineering Co., Ltd., and the front end shape is φ1.5, length 15 mm. Table 1 shows the results of examining the repulsive force (N) received by the front terminal 40 for each length L (mm) of displacement amount by performing an insertion operation to a displacement amount of 15 mm. Further, the change rate of the repulsive force is shown in Table 2. The repulsive force for each displacement amount for each example in Table 1 is shown in the graph of FIG.

As shown in Tables 1 and 2 and FIG. 3, when the curing time t is 1 day (Example 2) or more, the repulsive force increases as the displacement amount L increases. This result indicates that the silicone rubber is more cured from the end 10 a side to the 10 b side of the silicone rubber composition 30. Also, as the curing time t is extended to 0 days (Example 1) to 14 days (Example 5), the slope of the repulsive force becomes larger, ie, the longer the curing time is, the more the edge of the silicone rubber composition 30 It shows that it has hardened to the 10b side (inside).
From the above results, it was shown that the method for measuring the degree of cure of the silicone rubber composition of the present invention can measure the state of cure of the silicone rubber composition in a detailed and accurate manner.

  While certain embodiments have been described, these embodiments have been presented by way of example only, and are not intended to limit the scope of the invention. These embodiments can be implemented in other various forms, and various omissions, replacements, and modifications can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the invention described in the claims and the equivalents thereof as well as included in the scope and the gist of the invention.

  According to the present invention, it is possible to obtain a method of measuring the degree of cure of a silicone rubber composition that can measure the degree of cure of the silicone rubber composition accurately and easily.

Reference Signs List 10 container 10a, 10b end 11, 21 screw structure 20A, 20B lid 30 silicone rubber composition 40 tip terminal 41 load measuring device D, F direction L length

Claims (7)

A method of measuring the degree of curing of a silicone rubber composition, comprising
Filling the container with the silicone rubber composition,
Curing at least a part of one end side of the silicone rubber composition,
A rod-like repulsive force measuring means is inserted toward the cured part from the other end side of the silicone rubber composition opposite to the cured one end side,
A method for measuring the degree of cure of a silicone rubber composition, which measures the repulsion force received by the repulsion force measuring means for each length in which the repulsion force measuring means is inserted. The container has a cylindrical shape in which at least one end can be airtightly closed by a lid,
When the curing is performed, one end side of the container to be cured is opened, and the other end side is closed by a lid portion,
The lid of the other end side is removed when inserting the repulsion measurement means, and the repulsion measurement means is inserted into the silicone rubber composition from the other end side. Method of measuring degree of cure of silicone rubber composition.   The method for measuring the degree of cure of a silicone rubber composition according to claim 1 or 2, wherein the silicone rubber composition contains a polyorganosiloxane and a crosslinking agent.   The method for measuring the degree of cure of a silicone rubber composition according to any one of claims 1 to 3, wherein the length of the repulsive force measurement means is 10 to 40 mm and the diameter is 1 to 2.5 mm.   The method for measuring the degree of cure of a silicone rubber composition according to any one of claims 1 to 4, wherein the insertion of the reaction force measurement means is performed by a load tester at a tip terminal moving speed of 1 to 10 mm / min.   The method for measuring the degree of cure of a silicone rubber composition according to any one of claims 1 to 5, wherein the container has a cap that can be screwed at both ends and can be hermetically sealed by the cap. . The container for an inner surface shape of the container, the tubular length is 5 to 40 mm, the cross-sectional area of the tubular is 75～750Mm ^2, silicone according to any one of claims 2 to 6 Method of measuring degree of cure of rubber composition.

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