JP2000336340A - Polyurethane sealant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject sealant having a specific tack-free time and capable of providing a body sealer having physical properties excellent in elongation, heat resistance, etc., within a wide temperature range, especially low temperatures without substantially containing chlorine by including a specific amount of a colloidal silica. SOLUTION: This two-part type polyurethane sealant has <=5 min tack-free time, contains 0.2-5 wt.% of a colloidal silica and is obtained by regulating the apparent density within the range of 0.2-0.9 g/cm3. The above sealant is usually obtained by mixing a first liquid containing an isocyanate (e.g. diphenylmethane diisocyanate) with a second liquid which is a curing agent containing a polyol (ethylene glycol or propylene glycol). When the above sealant is used, a foaming agent can be used to expand the sealant. Thereby, the sealant can be filled to all the corners of spot welded parts and is useful for improving rust preventing and waterproof performances.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-part urethane sealant for sealing a joint between a body of an automobile or the like and a door or the like.

[0002]

2. Description of the Related Art A body sealer is used for waterproofing, rustproofing, dustproofing and improving design of a steel plate joint portion of an automobile body or the like. Conventionally, PVC plastisol has been used as this body sealer. PVC plastisol is a one-component material and has good workability because it is a heat-cured material, but it has problems such as discoloration due to ultraviolet rays, cracking and peeling due to vibration, and the like. Furthermore, since dioxin is generated at the time of disposal and incineration, it is necessary to provide a detoxification facility at the time of incineration in order to prevent environmental pollution. On the other hand, although the urethane-based sealing material does not contain chlorine, its curability and physical properties are insufficient for use as a body sealer. For example, urethane-based sealing materials used as jointing materials for building materials have a long curing time of several hours, and are designed to follow the movement of the building by softening the hardness and increasing the elongation to about 500%. Also, the low-temperature properties and the heat resistance exceeding 100 ° C. are significantly reduced. In addition, urethane-based sealants used as adhesives for windshields and lamps of automobiles have a slow curing property and do not require heat resistance because they are used after the body painting line. It is a material whose emphasis is on emphasis and the elongation properties at low temperatures are not considered. Therefore, development of a sealing material for a body sealer that can be used for sealing a steel plate joint has been desired.

[0003]

SUMMARY OF THE INVENTION The present invention does not substantially contain chlorine, has a fast curing effect of being cured immediately after application, has no physical property deterioration at a baking temperature in a coating process of an automobile manufacturing line, and has an excellent property in a steel plate joint. There has been a long-awaited need for a body sealer that has a particularly large elongation as a material that can penetrate into small gaps, and after coating, has a waterproof property, a rust-proof property, and a physical property capable of withstanding repeated stress at low temperatures.

[0004]

Means for Solving the Problems In view of the above circumstances, the present inventors have conducted intensive studies on a method for producing a polyurethane sealant substantially containing no chlorine. As a result, a body sealant having excellent physical properties was obtained, and the invention was completed. That is, the present invention provides the following (1) to (7). (1) A two-pack type polyurethane sealant having a tack-free time of 5 minutes or less, the sealant containing 0.2 to 5 wt% of colloidal silica, and an apparent density of 0.2 to 0.9 g / Polyurethane sealant in the cm ³ range. (2) The two-pack polyurethane sealant according to (1) is obtained by reacting a prepolymer (A) obtained from an active hydrogen compound and an isocyanate with a curing agent (B), and the prepolymer (A) is cured. 2 to 2 parts of colloidal silica in at least one part of the agent (B)
A polyurethane sealant containing 10 parts. (3) The polyurethane sealant according to (1) or (2), wherein the polyurethane sealant is foamed using a physical foaming agent. (4) A polyurethane sealant using liquid carbon dioxide as the physical foaming agent according to (3). (5) Diphenylmethane diisocyanate (MDI), carbodiimide-modified diphenylmethane diisocyanate
(Liquid MDI), isocyanate selected from at least one of polymeric MDI (PMDI) and a polyol compound, the NCO group content% (sometimes referred to as NCO%) is 13 to 26.
%. The polyurethane sealant according to any one of (2) to (4), wherein the prepolymer (A) manufactured in the range of% is used. (6) The polyurethane sealant according to (2) to (4), wherein the prepolymer (A) and the curing agent (B) are mixed by a collision mixing method using a high-pressure foaming machine. (7) A sealant for a body sealer containing the polyurethane sealant according to (1) to (6).

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The polyurethane for a body sealer according to the present invention will be described in detail. In the following, the term "part" means "part by weight" unless otherwise specified.
The polyurethane for a body sealer according to the present invention is a two-component polyurethane sealant having a tack-free time of 5 minutes or less, a sealant containing 0.2 to 5 wt% of colloidal silica, and an apparent density of 0.2. ~
It is in the range of 0.9 g / cm ³ . This two-pack type polyurethane sealant is usually obtained by mixing a first liquid containing isocyanate and a second liquid which is a curing agent containing polyol. When used as these sealants, they can be foamed using a foaming agent.
First, a method for producing these two-pack type polyurethane sealants and production of raw materials thereof will be described.

[Production method of two-component polyurethane sealant] The two-component polyurethane sealant used in the present invention has a tack-free time of 5 minutes or less, and contains 0.2 to 5% by weight of colloidal silica in the sealant, preferably Contains 1-5 wt%, apparent density 0.2-0.9g
/ cm ³ , which is usually obtained by mixing the first liquid containing isocyanate and the second liquid which is the curing agent (B) containing polyol as described above.

{First Liquid} As the isocyanate contained in the first liquid, diphenylmethane diisocyanate (MD
I), aromatic diisocyanates such as tolylene diisocyanate (TDI), xylylene diisocyanate (XDI), tetramethyl xylylene diisocyanate (TMXDI), isophorone diisocyanate (IPD)
Any aliphatic diisocyanate such as I), hexamethylene diisocyanate (HDI), hydrogenated xylylene diisocyanate (hydrogenated XDI), and hydrogenated diphenylmethane diisocyanate (hydrogenated MDI) may be used as long as it is used for ordinary urethane. Prepolymerization stabilizes the curability and physical properties of the resulting sealant even if the curing conditions of the sealing material fluctuate, so use isocyanate and an active hydrogen compound in addition polymerization and use a prepolymer having a terminal isocyanate group. Is preferred.

(Prepolymer (A)) The prepolymer (A) used in the present invention is a reaction product of an isocyanate and an active hydrogen compound and usually has an isocyanate terminal. The production method is not particularly limited, but isocyanate and the active hydrogen compound are generally blended at once, or one of them is charged first, and the other is added later.
It is obtained by reacting at 20 ° C. for 1 to 150 hours. In order to speed up the reaction, a known catalyst may be added and reacted for production. When producing the prepolymer (A), the molar ratio of isocyanate groups to active hydrogen (NCO / H ratio) can be arbitrarily selected according to the required viscosity of the polyurethane and the NCO%, but a high-pressure foaming machine is used. For this purpose, a low-viscosity material is desirable, the dilution is preferably carried out in the presence of a free isocyanate monomer, and more preferably 8 or more. The average molecular weight of the polyol used is not particularly limited, but is generally 300 to 50,000, preferably
500 to 20,000, most preferably 700 to 10,000.

(Isocyanate used for producing prepolymer (A)) As the isocyanate to be reacted with the active hydrogen compound, an isocyanate used in a usual polyurethane resin composition can be used. Preferably, a polyisocyanate having two or more molecular terminal isocyanate groups in the molecule is used. For example, tolylene diisocyanate (TDI), hydrogenated tolylene diisocyanate, diphenylmethane diisocyanate (MDI), polymeric MDI (P
MDI), xylylene diisocyanate (XDI), aromatic isocyanates such as 1,5-naphthalenediisocyanate (NDI), aliphatic isocyanates such as hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPD
A) alicyclic polyisocyanates such as I), hydrogenated XDI (H6XDI), hydrogenated MDI (H12MDI), norbornane diisocyanate methyl (NBDI), and carbodiimide-modified isocyanates and isocyanurate-modified isocyanates of the above isocyanates.
Of these, carbodiimide-modified isocyanate of MDI is M
DI is reacted at high temperature in the presence of phosphoric ester to form carbodiimidation.
What is added to MDI is used, which is called liquid MDI because it is liquid at room temperature, and its NCO% is generally 25 to 25%.
It is 31%. Among these, use of MDI and a modified product of MDI is particularly preferred, and these may be used in combination of two or more. These may be used alone when producing the prepolymer (A), or a plurality of them may be used in combination as needed.

(Active Hydrogen Compound Used in Prepolymer (A) Production) An active hydrogen compound used in a usual polyurethane resin composition can be used. The active hydrogen compound used in the present invention is a polyol (a compound having two or more hydroxyl groups at molecular terminals), or a compound having active hydrogen that reacts with isocyanate such as thiol or amine compound. Examples of the polyol include polyhydric alcohols having relatively low molecular weight, polyether polyols, polyester polyols, polyether polyols, and modified products of polyester polyols. More specifically, relatively low molecular weight polyhydric alcohols include ethylene glycol (EG) and diethylene glycol (DE).
G), propylene glycol (PG), dipropylene glycol (DPG), 1,3-butanediol (1,3-B
D), dihydric alcohols such as 1,4-butanediol (1,4-BD), 4,4'-dihydroxyphenylpropane, 4,4'-dihydroxyphenylmethane, glycerin, 1,1,1-trimethylol Examples include trihydric alcohols such as propane (TMP) and 1,2,5-hexanetriol, and polyhydric alcohols having a valency of 4 or more such as pentaerythritol, glucose, sucrose, and sorbitol. Examples of polyether polyols include polyether polyols and tetrahydrofurans obtained by addition polymerization of one or more kinds of relatively low molecular weight polyhydric alcohols with one or more kinds of ethylene oxide, propylene oxide, butylene oxide and the like. And polytetramethylene ether glycol (PTMEG) obtained by ring polymerization. As the polyester polyol, one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, glycerin, trimethylolpropane and the like or other low molecular polyols and glutaric acid, adipic acid, sebacic acid, terephthalic acid And polyester polyols obtained by condensation polymerization with one or more kinds of low-molecular dicarboxylic acids or oligomeric acids, or other low-molecular dicarboxylic acids or oligomeric acids, and ring-opening polymerization such as caprolactone. As a modified product of the polyether polyol or polyester polyol, acrylonitrile, styrene,
Polymer polyols obtained by graft polymerization of an ethylenically unsaturated compound such as methyl methacrylate are exemplified. Examples of the amine compound include aliphatic diamines such as ethylenediamine and aromatic diamines. Among the active hydrogen compounds, polyols are preferable, and polyhydric alcohols and polyethers having a relatively low molecular weight are more preferable because the water resistance of the resulting sealant having a low material viscosity is further improved. These active hydrogen compounds may be used alone or in combination as necessary. The first liquid preferably contains 2 to 10 parts of colloidal silica based on 100 parts of the total amount of isocyanate and polyol.

{Second Liquid} The second liquid is usually called a curing agent because curing is started by mixing with the first liquid. The present curing agent (B) contains a polyol, and if necessary, colloidal silica, a crosslinking agent, a catalyst, a foam stabilizer, and a foaming agent can be used in combination. Also, plasticizers used for ordinary urethane molding within a range that does not impair the effects of the present invention,
Various additives such as antioxidants, ultraviolet absorbers, light stabilizers, antioxidants, coloring agents for pigments and dyes, and dispersants can be blended. These other additives may be partially or entirely incorporated into the first liquid as long as the effects of the present invention are not impaired.

(Polyol) The polyol used for the curing agent (B) may be the same as or different from that used for the first liquid, and they may be used alone or in combination. Examples of the polyol include polyhydric alcohols having relatively low molecular weight, polyether polyols, polyester polyols, polyether polyols, and modified products of polyester polyols. More specifically, relatively low molecular weight polyhydric alcohols include ethylene glycol (EG) and diethylene glycol (DE).
G), propylene glycol (PG), dipropylene glycol (DPG), 1,3-butanediol (1,3-B
D), dihydric alcohols such as 1,4-butanediol (1,4-BD), 4,4'-dihydroxyphenylpropane, 4,4'-dihydroxyphenylmethane, glycerin, 1,1,1-trimethylol Examples include trihydric alcohols such as propane (TMP) and 1,2,5-hexanetriol, and polyhydric alcohols having a valency of 4 or more such as pentaerythritol, glucose, sucrose, and sorbitol. Examples of polyether polyols include polyether polyols and tetrahydrofurans obtained by addition polymerization of one or more kinds of relatively low molecular weight polyhydric alcohols with one or more kinds of ethylene oxide, propylene oxide, butylene oxide and the like. And polytetramethylene ether glycol (PTMEG) obtained by ring polymerization. As the polyester polyol, one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, glycerin, trimethylolpropane and the like or other low molecular polyols and glutaric acid, adipic acid, sebacic acid, terephthalic acid And polyester polyols obtained by condensation polymerization with one or more kinds of low-molecular dicarboxylic acids or oligomeric acids, or other low-molecular dicarboxylic acids or oligomeric acids, and ring-opening polymerization such as caprolactone. As a modified product of the polyether polyol or polyester polyol, acrylonitrile, styrene,
Polymer polyols obtained by graft polymerization of an ethylenically unsaturated compound such as methyl methacrylate are exemplified. The amount to be used may be appropriately set according to the desired physical properties of the product, but usually 50 to 90 parts per 100 parts of the curing agent (B).
Department.

(Colloidal silica) Colloidal silica is finely divided silica that can exist in a stable dispersion state in a system, and is thixotropic (thixotropic) by the action of silanol groups (Si-OH) present on the surface. A liquid resin (urethane,
Epoxy, unsaturated polyester, etc.). The average particle size is not particularly limited, but the average particle size of the colloidal silica is generally 1 to 100 nm, preferably 5 to 50 nm. The specific surface area measured by the BET method is usually 50
~ 1000 m2 / g. Hydrophilic (Si-O
H) and hydrophobicity (SiO ²⁺ -CH ₃ ), but in the case of the present invention, any type can be used. These are 0.2 to 5% by weight, preferably 1 to 5% by weight in the sealant.
It may be added so as to contain it. Generally, at least one of the prepolymer (A) and the curing agent (B) is added.
It is preferable that 2 to 10 parts of colloidal silica be contained in 0 part, and it is particularly preferable that 2 to 10 parts be contained in 100 parts of the polyol in the curing agent (B). Thixotropic agents other than colloidal silica, for example, synthetic magnesium silicate, sodium silicate, lithium silicate (for example, Laponite manufactured by Nippon Silica Kogyo Co., Ltd.) may be used in combination.

(Crosslinking Agent) As the curing agent (B), a crosslinking agent can be used if necessary. As the crosslinking agent, a known crosslinking agent for urethane can be used, but it is preferable to use a low-molecular-weight polyhydric alcohol. Although the molecular weight of the low molecular weight polyhydric alcohol is not particularly limited, it is usually 60 to 300. Examples of low molecular weight polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, pentanediol, hexanediol, trimethylolpropane, 1,3-
Dihydric alcohols such as butanediol, 1,4-butanediol, 4,4'-dihydroxyphenylpropane, 4,4'-dihydroxyphenylmethane, glycerin, 1,1,1-trimethylolpropane, 1,2,5 -Trihydric or higher polyhydric alcohols such as hexanetriol and pentaerythritol.
The amount used may be appropriately set according to the desired physical properties of the product, but is usually 5 to 40 parts in 100 parts of the curing agent (B).

(Catalyst) The catalyst used in the present invention is, for example, an organotin compound such as dibutyltin dilaurate, dioctyltin dimaleate, stannous octylate, dibutyltin oxide, or tetrabutyl titanate. Organic titanium compounds, lead naphthenate, organic lead compounds such as lead octylate, organic metal catalysts such as organic bismuth compounds such as bismuth neodecanoate and bismuth octylate, triethylenediamine, triethylamine, tetramethylenediamine, N-methylmorpholine, Tertiary amines such as N, N-dithymethanolamine can be used alone or in combination. The amount to be used may be appropriately set according to the intended physical properties of the product, but usually the curing agent (B) 10
0.1 to 3 parts in 0 parts.

(Blowing Agent) As the blowing agent used in the present invention, any of a physical blowing agent and a chemical blowing agent can be used.
Specifically, as the physical foaming agent, chlorofluorocarbon, alternative chlorofluorocarbon, methylene chloride, carbon dioxide, air and the like are used, and as the chemical foaming agent, water and the like are used. It is preferable to use a physical foaming agent, and it is particularly preferable to use carbon dioxide gas or air, and it is most preferable to use liquid carbon dioxide gas from the viewpoint of miniaturizing the bubbles of the obtained foaming agent. The amount used can be appropriately selected so that the resin density becomes a predetermined apparent density. In order to maintain the apparent density at 0.2 to 0.9 g / cm ³ , the amount used can be extremely small. For example, 0.05 parts to 100 parts of the total amount of the prepolymer (A) and the curing agent (B)
0.5 parts. If it is 0.5 parts or more, the density is reduced, and the physical properties are reduced. In such a case, it is necessary to take into account the content of a component which can act as a foaming agent contained in the raw material, that is, in the first and second liquids, as an addition amount. Such components include, for example, water content. After adding these, water or the like may be used in combination as a chemical foaming agent.

(Foam stabilizer) As the foam stabilizer used in the present invention, materials used for urethane molding can be used. Since it is preferable to increase the proportion of closed cells for the purpose of imparting waterproofness, it is preferable to use a brand for forming closed cells, which has a strong foam-regulating power usually used for rigid foams. For example, L-5420, SZ-1 manufactured by Nippon Unicar
627 and TG-8462 manufactured by Goldschmidt. The amount to be used may be appropriately set in accordance with the intended physical properties of the product, but is usually 0.2 to 3 parts per 100 parts of the curing agent (B).
Department.

{Production equipment for polyurethane sealant, etc.}
The polyurethane sealant is obtained by mixing a first liquid containing isocyanate and a second liquid which is a curing agent (B) containing a polyol. The obtained sealant may be separately applied to the target by a coating device, but is usually applied directly to the target after mixing. As equipment for stirring and mixing for producing the polyurethane sealant, pumps having quantitative properties for feeding raw materials, for example, a gear pump, a combined use of a plunger pump and a throttle valve, and the like, a mechanical rotary mixer for mixing, A static mixer or the like can be used. In particular, it is preferable to mix and stir at high pressure, and there is a quantitative property for feeding the raw material of 100 kg /
It is preferable to use a pump that can generate a high pressure of about cm2. Examples of such a high-pressure pump include an axial piston, a gear, and a radial. A stirring and mixing head is most preferable for stirring and mixing the two liquids. If the present head is used, it is possible to mix a fast-curing material and then wash it without a solvent. First liquid and second liquid
The mixing ratio of the liquid can be appropriately set according to the required physical properties of the product, and is usually 1: 3 to 3: 1 by weight. Further, the polyurethane sealant is suitable as a sealant for sealing a joint of a body of an automobile or the like and a door or the like.
Other materials may be used in combination as long as the effects of the present invention are not impaired.

[Two-component polyurethane sealant] The tack-free time of the two-component polyurethane sealant used in the present invention is 5 minutes or less. The content of the colloidal silica in the sealant obtained after mixing and curing the two liquids is 0.1%.
The content is 2 to 5 wt%, preferably 1 to 5 wt%, and the apparent density is in the range of 0.2 to 0.9 g / cm ³ . When producing a polyurethane sealant, it is preferable to foam using a foaming agent, since the waterproofness and the rust prevention effect are improved. When the polyurethane sealant thus obtained is a foam, the ratio of closed cells in the cells is more preferably 50% or more. The polyurethane sealant obtained by the above-mentioned method has a tack-free time of 5 minutes or less and shows rapid curability, and is exposed to the baking temperature (150 ° C) in the coating process for 1 and 2 hours, then returned to 25 ° C and measured. The obtained elongation rate is 150% or more, and shows an elongation rate of 50% or more even at a temperature below freezing, for example, -30 ° C. 20 at 25 ° C in tensile strength
kgf / cm ² or more, showing a sub-zero eg -30 ° C. even 40 kgf / cm ² or more. Adhesion to steel plate is good, and if there is a gap in the joint, it is thought that it can withstand repeated stress by foaming and entering into fine parts, and at the same time painting with steel plate Can also.

[0020]

By using a polyurethane sealant containing colloidal silica in a specific range, it is possible to obtain a body sealer which extends over a wide temperature range, especially at a low temperature, and has excellent physical properties such as heat resistance. Further, by using the foam material, the sealing material can be filled to every corner of the spot welded portion, and rust prevention and waterproof performance can be improved.

[0021]

Example 1) Preparation of Materials Used Preparation of Prepolymer (A-1): 134 g of PPG Diol-3000 (OHv = 37, average number of functional groups = 2, manufactured by Mitsui Chemicals, Inc.) in a separable flask equipped with a stirrer, 68.8 g of MDI (manufactured by Mitsui Chemicals) and 68.8 g of MDI-LK (NCO% = 28, manufactured by Mitsui Chemicals), which is a liquid MDI modified with carbodiimide, were charged. After reacting at 80 ° C. for 3 hours under a nitrogen stream and aging at room temperature for 1 day, NCO% = 14, viscosity (cp / 25
C) = 600 to obtain a low viscosity prepolymer. The NCO / H ratio at this time was 11.2.

Preparation of prepolymer (A-2): PPG Diol-2000 (OHv = 56, average number of functional groups = 2, using the same apparatus as A-1)
87g, MDI 68.8g and MDI-LK 68.8g
Charge and react at 80 ℃ for 3 hours.
A low-viscosity prepolymer with O% = 17 and viscosity (cp / 25 ° C.) = 800 was obtained. The NCO / H ratio at this time was 11.5.

Preparation of prepolymer (A-3): PPG Diol-2000 (OHv = 56, average number of functional groups = 2,
80g, MDI 68.8g and MDI-LK 68.8g
After charging and reacting at 80 ° C for 1 hour, 7.8 g of colloidal silica (Aerosil # 200; manufactured by Nippon Aerosil Co., Ltd.) was added, and the mixture was heated to 80 ° C.
The reaction was performed for 3 hours. The analysis value after 1-day aging showed that a prepolymer having thixotropic properties was obtained at NCO% = 17. The NCO / H ratio at this time was 12.5. This prepolymer has a thixotropic property (the viscosity ratio of 1 rotation to 10 rotations by a B-8 rotational viscometer is 3.5), but apparently the viscosity is high,
A pump with a shear, such as an axial piston, breaks thixotropy and becomes in the same state as a low-viscosity liquid.
By adjusting the liquid pressure to about 100 kg / cm2, the liquid could be sent without any problem.

Preparation of prepolymer (A-4): PPG Diol-1000 (OHv = 112, average number of functional groups =
2, Mitsui Chemicals, Inc.) 33 g, MDI 68.8 g and MDI-LK 68.8
g, and let it react at 80 ° C for 3 hours.
A low viscosity prepolymer with NCO% = 23 and viscosity (cp / 25 ° C.) = 400 was obtained. The NCO / H ratio at this time was 15.2.

[0025]

[Table 1]

Preparation of curing agent (B-1): 850 g of ethylene glycol (EG) as a low molecular weight polyhydric alcohol-based crosslinking agent,
EO Cap Triol EP-550N (OHv = 54, Mitsui Chemicals) 5
00 g, terminal EO cap diol ED-56 (OHv = 56, manufactured by Mitsui Chemicals, Inc.) 2500 g, dibutyltin dilaurate (DBT
DL) and 20 g of an amine catalyst (Minico L-1020, manufactured by Active Materials Chemical Co., Ltd.) were charged into a dissolver mixer manufactured by Inoue Seisakusho in a ratio of 20 g, and stirred and mixed at a normal temperature of 1,000 rpm for 1 hour. Next, 200 g of colloidal silica (Aerosil # 200) was rotated 50 times.
The solution was gradually added at a rate of 0 rpm. After the addition of the entire amount, the rotation speed was increased to 1000 rpm, and the mixture was stirred for 1 hour. Then
50 g of a foam stabilizer L-5420 (manufactured by Nippon Unicar) was added, followed by stirring and mixing for 15 minutes to obtain a curing agent (B-1).

Preparation of curing agent (B-2): Using the same apparatus as used for preparing the curing agent (B-1), 1840 g of EP-550N and PTMEG-100
2 (polytetramethylene ether glycol having a molecular weight of 1000, manufactured by DuPont) 2760 g, 1,4-BD (1,4-butanediol) 1320 g, Aerosil # 200 300 g, L-5420 50 g,
It was prepared under the same conditions as B-1 with 25 g of DBTDL and 25 g of L-1020.

Preparation of curing agent (B-3): Using the same apparatus as used for preparing the curing agent (B-1), 1840 g of EP-550N and 55 ED-56 were used.
20g, 1320g of 1,4-BD, 600g of Aerosil # 200, L-5420
100g, DINA (diisononyl adipate) as plasticizer
Was prepared under the same conditions as B-1 with 2540 g of DBTDL, 40 g of DBTDL, and 40 g of L-1020.

Preparation of curing agent (B-4): R-45HT (terminal hydroxyl group-containing polybutadiene, OHv = 46.6, manufactured by Idemitsu Petrochemical Co., Ltd.) using the same apparatus as used for preparing curing agent (B-1) 11980g,
1,4-BD 1790g, Aerosil # 200 600g, L-5420 100
g, DINA: 5430 g, DBTDL: 50 g, L-1020: 50 g, prepared under the same conditions as B-1.

Preparation of curing agent (B-5): Using the same apparatus as used for preparing curing agent (B-1), 4320 g of PTMEG-1000, 1,4-BD
580g, Aerosil # 200 200g, L-5420 50g, DBTD
L was 25 g and L-1020 was 25 g, and prepared under the same conditions as B-1.

Preparation of curing agent (B-6): 1840 g of EP-550N, ED-5
6 to 5520 g, 1,4-BD to 1320 g as a catalyst, DBTDL to 25 g, L-1
020 was charged into the same dissolver as B-1 at a rate of 25 g, and 1
Stir and mix for hours. The curing agent is obtained by removing colloidal silica and silicone as a foam stabilizer.

[0032]

[Table 2]

(Evaluation and test methods) Gelation time: Predetermined amount of prepolymer (A) liquid and curing agent (B)
Measure the solution in a beaker, vigorously stir with a spatula,
Time until liquid loses fluidity.

TFT: Abbreviation of tack-free time, which is the time from mixing of the prepolymer (A) and the curing agent (B) until the resin does not transfer to the finger even when the cured product surface is touched.

-Droop resistance: A slump test jig based on JIS A-5758 (building sealing material) was used.
After being applied to a slump test jig, it was installed vertically in an atmosphere at 25 ° C. and the state of droop was observed. ◎ indicates less than 1 mm, Δ indicates less than 1 to 2 mm, and × indicates 2 mm or more.

Curing Conditions for Resin After curing to TFT at room temperature, the resin was cured at 100 ° C. for 1 hour, then returned to room temperature and cured for 1 day. In addition to RT (room temperature), -30 degree atmosphere,
After a heat resistance test at 150 ° C. (1 and 2 hours) and after a boiling test (1 hour), the sample was left at 25 ° C. for 7 days, and then subjected to a physical property test.

Physical property test: Conducted according to JIS K-6301. The hardness is measured using a JIS-A type hardness tester, the tensile test is performed using A & D Tensilon, the speed is 500 mm / min, the test specimen is a JIS-2 dumbbell, and the tear strength is B type. I went in. As a result, hardness (JIS-A), tensile strength (Ts: kgf / cm
2), elongation (EL:%), and tear strength (Tr: kgf / cm) were measured.

・ Adhesion test with iron plate (180 ° peel test): JI
S G-3141 (SPCC, SD) Cationic electrodeposition coating method Apply the material on an electrodeposition coating iron plate of U600 (manufactured by Testpiece Co., Ltd.) and cure it under the above conditions. The tensile strength (kgf / in) was measured at a speed of / min.

Rust prevention test: After applying a cross cut reaching the base iron plate to the electrodeposited iron plate, applying a sealer material
Cure at 25 ° C for 7 days. After immersing the test piece in water at 40 ° C. for 7 days, the condition of the cross cut portion is observed. The sample having red rust was evaluated as x, the sample with metallic luster remained as ○, and the sample with no metallic luster but no red rust was evaluated as Δ.

Waterproofing test: It was performed according to the “water permeability test” method described in JIS A-6910 (multilayer finish coating material). The test sample was prepared by using a Toray polyester spunbond (H50901, thickness = 0.31 mm, basis weight = 90 g / m2, air permeability = 120 c as a base).
c / cm2 / sec), apply a sealer material to a thickness of 5 mm, and then apply an acrylic urethane paint (Color Top SS, manufactured by Asia Industry Co., Ltd.)
Was applied at a rate of 150 g / m 2 and cured at 25 ° C. for 14 days. Next, a funnel was set up on the surface of the sealer, and the periphery was fixed with a silicone sealant, and the operation was performed at a water head of 250 mm. After 24 hours, the case where the water head height was 230 mm or more was evaluated as ○, 200 to 229 mm as Δ, and less than 200 mm as X.

Example 1 (A-1) was added to 10
0 parts by weight, 41.1 parts by weight of (B-1) as a curing agent, and molded by Toho Kikai's high pressure foaming machine NR210 type machine (axial piston high pressure pump, collision mixing type mixing head / rod) No solvent is used in the mechanical cleaning by taking in and out). Addition of carbon dioxide gas is (A-1) + (B-1)
0.2 wt% of the total amount of
It was press-fitted using a triple plunger pump. The NCO Index (NCO / H) in this case is 1.1. The composition was applied onto an electrodeposited iron plate and a Teflon-coated mold, and the workability, physical properties and adhesiveness were measured. As a result, the liquid discharged from the mixing bed had a thixotropic property by being charged with carbon dioxide gas into the curing agent line, and the silicon foam stabilizer and colloidal silica in the system to retain the fine bubbles. It had a so-called shaving cream shape, did not level, and had a good dripping resistance of 1 mm or less. Reactivity is tack free time 2 at 25 ° C
Min, physical properties are hardness (JIS-A) 61, tensile strength 23kgf / cm2, elongation 210%, tear strength 12kgf / cm, cured product density 0.6g / cm3
When observing the cross section of the sealer, "fine bubbles"
And the whole was foamed in a homogeneous state. The curability was fast, the physical properties were good, and the material was well-balanced as a body sealer. Physical properties at -30 ° C showed a tensile strength of 68 kgf / cm2 and an elongation of 75%. The results of the heat resistance test at 150 ° C x 1 and 2 hours assuming an automotive paint line show that the tensile strength is 21kgf / cm2, the elongation is 180%, and the physical properties at 25 ° C are not so different. Deterioration is considered to be no problem. 7 after immersion in boiling water for 1 hour
After drying for a day and examining the degree of deterioration, the physical properties were 25 ° C. and there was not much difference, and the results were good. In addition, in the adhesion test with the electrodeposition coated iron plate, the material was destroyed by the 180 degree peel test with no surface treatment, and the cohesive failure of the material was observed at a strength of 2.5 kgf / in or more. Further, a two-pack type acrylic urethane paint (Color Top SS, manufactured by Asia Co., Ltd.) was applied to the surface, but the adhesion to the paint was good, and rubbing with a metal piece did not confirm peeling. In addition, as a result of the rust prevention test, which was separately tested, the metallic luster remained in the cross cut part, and the evaluation was “○”. It was good. As described above, this material was suitable as an automobile body sealer.

(Example 2) 10% of (A-2) was used as a prepolymer.
0 parts by weight, 63.2 parts by weight of (B-2) as a curing agent, and a low pressure foaming machine (gear pump, rotary mixing head / solvent cleaning type) manufactured by Toho Machinery Co., Ltd. were used for molding. Liquid carbon dioxide gas was injected directly into the mixing head at a rate of 0.1 wt% based on the total amount of (A-1) + (B-1) using a triple plunger pump. The NCO Index in this case is 1.1. The same coating operation as in Example 1 was performed, but fine bubbles were generated by the rotation of the rotor of the mixing head, and the liquid could be discharged in a state where the shaving cream was held, and the dripping resistance was also good. Reactivity is tack free time at 25 ° C for 3 minutes, physical properties are hardness (JIS-A) 76, tensile strength 29
kgf / cm2, elongation 200%, tear strength 13 kgf / cm, cured product density 0.7 g / cm3, and observing the sealer cross section,
"Fine bubbles" were formed and the whole foamed in a homogeneous state. The curability was fast, and the physical properties after the heat resistance test at low temperature and at 150 ° C. were good, and the material was well-balanced as a body sealer. Further, the adhesion test with the electrodeposition coated iron plate also showed cohesive failure of the material, and the adhesion was good.
Further, the rustproofing property was “○”, and the waterproofness was 245 mm, which was “○”.

Example 3 (A-3) was used as a prepolymer in 10
0 parts by weight, 120 parts by weight of (B-3) was used as a curing agent, and molding was performed by attaching a resin disposable static mixer to a low-pressure foaming machine (DG-103) made by Toho Machinery. went. In this system, the amount of colloidal silica is 4.3 parts per 100 parts of the total amount of the liquid (A) + (B). Foamed by moisture. NCO Index in this case
Is 1.1. The same coating operation as in Example 1 was performed,
No sagging occurred due to the effect of the colloidal silica, and foaming started over time. Reactivity is tack free time at 25 ° C for 4 minutes, physical properties are hardness (JIS-A) 80, tensile strength 36
kgf / cm2, elongation 230%, tear strength 17kgf / cm, cured product density 0.85g / cm3.When observing the sealer cross section, `` fine bubbles '' were formed and the whole was in a homogeneous state. It was foaming. The curability was fast, and the physical properties after the heat resistance test at low temperature and at 150 ° C. were good, and the material was well-balanced as a body sealer. Further, the adhesion test with the electrodeposition coated iron plate also showed cohesive failure of the material, and the adhesion was good. The rust resistance was “○”, and the waterproofness was 245 mm and was “○”.

Example 4 (A-4) was added as a prepolymer to 10
0 parts by weight and 200 parts by weight of (B-4) as a curing agent were used, and molding was performed using the same high-pressure foaming machine as in Example 1. In this embodiment, compressed air was injected into the liquid B line immediately before the head by a plunger pump so that the amount of the mixed air became 0.2 part with respect to (A) + (B) = 100 parts. In this case
The NCO Index is 1.1. The same coating operation as in Example 1 was performed, but fine bubbles were generated and the liquid could be discharged in a state where the shaving cream was held, and the dripping resistance was good. Reactivity is 3.5 minutes tack free time at 25 ° C,
Physical properties are hardness (JIS-A) 55, tensile strength 21kgf / cm2, elongation
170%, the tear strength was 13 kgf / cm, the cured product density was 0.4 g / cm3, and the cross section of the sealer was observed. As a result, "fine bubbles" were formed and the whole was foamed in a uniform state. The curability was fast, and the physical properties after the heat resistance test at low temperature and at 150 ° C. were good, and the material was well-balanced as a body sealer. Further, the adhesion test with the electrodeposition coated iron plate also showed cohesive failure of the material, and the adhesion was good. Further, the rust prevention property was “○”, and the result of the waterproof test was 235 mm, which was “○”.

(Comparative Example 1) Coating was performed using the same machine as in Example 2 with the combination of (A-2) as the prepolymer and (B-6) as the curing agent. As a result, since the foam stabilizer and colloidal silica were not blended in B-6, the bubbles of carbon dioxide gas could not be retained even by mixing with a rotating rotor, and the bubbles were broken immediately after discharge, resulting in poor dripping resistance. It was enough and leveled. However, the physical properties of the sheet-shaped product were good because the density was as high as 0.95 g / cm3. The sealer cross section was unevenly dispersed with large bubbles in places. It could not be molded as a sealing material. The rust prevention and waterproofness were “○”.

(Comparative Example 2) As a prepolymer, (A-1) was
00 parts by weight and 41.4 parts by weight of (B-1) as a curing agent were used, and molding was performed using the same high-pressure foaming machine as in Example 1. In the present embodiment, liquid carbon dioxide gas is introduced into the liquid B line immediately before the head, and the mixing amount is (A) + (B) = 100 parts for 100 parts.
The amount to become 0 parts was injected by a plunger pump. The NCO Index in this case is 1.1. When the same coating operation as in Example 1 was performed, a large amount of fine bubbles were generated due to a large amount of carbon dioxide mixed, and the liquid was discharged in a state where a soft shaving cream was maintained. The sagging resistance is very good, and the reactivity is tack free time of 3 minutes at 25 ° C, but the density is as low as 0.1 g / cm3, 25 ° C, -30 ° C, heat resistance and test with boiling water Results were very low.
Further, as a result of the rust prevention test, water penetrated into the inside, and the result was “×”, and the result of the waterproof test was that the water head was 100 mm, which was “×”.

[0047]

[Table 3]

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) C08G 18/78 C08G 18/78 C08K 3/36 C08K 3/36 C08L 75/00 C08L 75/00 // (C08G 18 / 10 101: 00) F-term (reference) 4H017 AA04 AA22 AA24 AA39 AB06 AC13 AD05 AE05 4J002 CK031 CK041 DE017 DE027 DJ016 EB017 EB067 FD327 GJ02 GN00 4J034 CA03 CA04 CA05 CA15 CB03 CB04 CC04 CC03 CC03 CC03 DA08 DF01 DF12 DF16 DF20 DF21 DG03 DG04 DG05 DG06 DG23 DQ04 DQ05 HA01 HA02 HA07 HA11 HA13 HB05 HC03 HC12 HC22 HC35 HC46 HC53 HC61 HC64 HC71 HC73 JA42 MA04 NA01 NA09 QA01 QB01 QB13 QC01 RA08

Claims (7)

[Claims] 1. A two-part polyurethane sealant,
A polyurethane having a tack-free time of 5 minutes or less, the sealant containing 0.2 to 5 wt% of colloidal silica, and an apparent density in a range of 0.2 to 0.9 g / cm ^3. Sealant. 2. The two-component polyurethane sealant according to claim 1, which is obtained by reacting a prepolymer (A) obtained from an active hydrogen compound and an isocyanate with a curing agent (B), and the prepolymer (A) is obtained. And a curing agent (B), wherein 100 parts of at least one of the curing agent (B) contains 2 to 10 parts of colloidal silica. 3. The polyurethane sealant according to claim 1, wherein said polyurethane sealant is foamed using a physical foaming agent. 4. A polyurethane sealant wherein liquid carbon dioxide is used as the physical foaming agent according to claim 3. 5. A diphenylmethane diisocyanate (MD)
I), carbodiimide-modified diphenylmethane diisocyanate (liquid MDI), a prepolymer produced by reacting a polyol compound with an isocyanate selected from at least one of polymeric MDI (PMDI) and having an NCO group content% in the range of 13 to 26% 3. The method according to claim 2, wherein (A) is used.
A polyurethane sealant according to any one of claims 1 to 4. 6. The polyurethane sealant according to claim 2, wherein the mixture of the prepolymer (A) and the curing agent (B) is obtained by a collision mixing method using a high-pressure foaming machine. 7. A sealant for a body sealer, comprising the polyurethane sealant according to claim 1.