JP2002541167A - Improved polyvinylsiloxane impression material - Google Patents

Abstract

  (57) [Summary] Described is an improved two-component polymerizable polyorganosiloxane composition having improved tear strength and wettability, particularly for use in making dental impressions. The improved tear strength is the result of the inclusion of a tetrafunctional polysiloxane having a vinyl content of 0.16-0.24 mmole / g. Working time is maintained by including a sufficient amount of a retarder to delay the onset of vinyl polymerization. Wettability is improved by including a surfactant so that the wetting contact angle to water for 3 minutes is less than 50 °. The selected surfactant has an HLB of 8-11, with a wetting contact angle achieved within less than 2 minutes, maintaining wetting throughout the working time of the impression, and substantially improving the quality of the impression . A low viscosity impression material is provided and contains a base component and a catalyst component. Both components are siloxane-based materials.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION The present invention is directed to improving room temperature curable polyorganosiloxanes that have good dimensional stability and good flow properties upon curing or curing. More particularly, the present invention is directed to an improvement in compositions of the general two component type, wherein the first component has a vinyl group and an organo having a hydrogen atom bonded to silicon. It is composed of an organopolysiloxane capable of undergoing an addition reaction with polysiloxane. The second component comprises a catalyst capable of promoting the addition of hydrogen atoms bonded to silicon atoms via vinyl groups. In certain embodiments, the materials of the present invention have high tear strength, low viscosity and are highly hydrophilic.

[0002] Some major uses of these room temperature curable polyorganosiloxane compositions are in dental applications. Such materials are typically used as impression materials, which ensure the reproducibility of oral hard and soft tissue morphology and allow for the dense finishing of crowns, bridges, dentures and other prostheses Things. For dental purposes, very good structural reproducibility of the replica is required to ensure a good replica for oral prosthesis fit. In this regard, dimensional changes during curing of the impression material must be avoided. Further, the surface of the replica or oral prosthesis must be free of irregularities, protrusions, pits and other defects. This is to ensure that castings and prostheses made from such impressions have a good surface quality, have a good fit, achieve good adhesion and also avoid irritation to delicate oral structures Pits and irregularities must be eliminated. These polyorganosiloxanes are also important in other fields where precise reproducibility is required, for example in metrology SEM experimental processing and jewelry manufacture.

When using a polyorganosiloxane as a dental impression material, various dark blue colors are generated. First, the tear strength tends to be low. When taking an impression effectively, it is necessary that the impression can be easily taken out of the dentition without tearing while preserving a particularly detailed impression in the thin peripheral area. In the past, various fillers have been added to improve tear strength. Such additions, at best, resulted in improvements on the order of about 10%, and such improvements were inadequate.

Paradiso is disclosed in WO 93/17654 by mixing a polyfunctional polysiloxane component containing tetrafunctionality with an impression material, and effecting an impression material matrix, particularly a linear polysiloxane having a vinyl end-blocked length. It discloses that further cross-linking was added in the direction to improve the tear strength. The paradiso composition consists of SiOH groups capped with Me ₃ Si units forming pendants from the molecules. These pendants only provide a mechanical or physical connection between the linear polysiloxane chains. This solution is non-chemical and the crosslink density is low and unsatisfactory.

[0005] Vogt et al. In EP 0 522 341 A1 use "QM" resin as a means of accelerating and increasing the cross-linking structure to produce a dental occlusion recording device with a very short processing time of 35-45 seconds. It is disclosed. The resin consists of _{SiO 4/2} of tetrafunctional as Q, consists building managing blocks such as monofunctional units _R 3 _{SiO 1/2} as M, wherein R is vinyl, methyl, ethyl or phenyl, or similar, Three or two functional units. Vogt reports that a small, elastomerically modified elastomer with higher tensile strength and hardness results. However, such materials have low strain values, lack flexibility and are unsuitable for taking impressions. Higher cross-linking ratios of QM resins also result in inadequate processing times which are very limited.

[0006] Another major well-known difficulty with polyorganosiloxane impression materials stems from their inherent lipophilic nature. Such properties make it difficult to reproduce hard and soft oral tissues because the oral environment is moist and often contaminated with saliva or blood. The lipophilicity of the impression material may result in a lack of surface detail on the delicate surface of the dentition.

A series of polyorganosiloxane impression material improvements have focused on adding a surfactant component to the dental impression material to reduce the lipophilic properties of the polysiloxane and make it more hydrophilic. Thus, Brian et al. In US 4,657,959 disclose the addition of an ethoxylated nonionic surfactant containing a siloxane or perfluoroalkyl solubilizing group to achieve a three minute water contact angle of about 65 °. Surfactants containing hydrocarbyl groups to dissolve or disperse the surfactant are mentioned, but the results achieved when ethyleneoxy groups were included were less than optimal.

[0008] As mentioned above, all silicone materials are known to be highly lipophilic. Therefore, these materials usually cannot of course wet the tooth surface, especially in the wet state. The hydrophilic nature can be achieved by adding a dipolar surfactant to the silicone. These additives do not normally dissolve in the silicone matrix, but rather form an emulsion in the silicone system. The rheological properties of these materials are characterized by typical non-Newtonian flow behavior with high yield stress and high shear stress. Non-bipolar surfactants include, for example, polyether-modified silicones and do not form unique micelles. The resulting emulsion is therefore not stable and tends to separate. However, the resulting multiphase system has a high yield stress, which can prevent flow on the tooth surface when no or low stress is applied. Hydrophilic silicones therefore usually exhibit only low flow properties under low stress.

A conventional “light body” formed from a two component system usually applies to one of two forms. The first is a hand mixing configuration where the two components are mixed by hand. The second is a self-mixing form when the two components have to be discharged from the cartridge through a static mixer.
In these two cases, the mixing of the two components is strongly influenced by the rheological properties of the components that make up the light body. In particular, in the most common self-mixing configuration, the force released from the cartridge is affected by the yield stress of the paste.

[0010] Due to the rheological substructure, many common hydrophilic silicones have a high yield stress. In order to utilize the small forces to release the material, a large static mixer must be employed. This leads to a high waste rate as more material remains in the mixer. It is therefore desirable to achieve a mixing that lowers the yield stress of the two respective paste components and minimizes the force required to remove the paste from the cartridge.

In ordinary light body products, high stresses must be applied to obtain the flow of impression material in the grooves and other details of the product. Low age type materials ("light bodies") are therefore always used in so-called "putty / wash" or "double mix" techniques in combination with high viscosity type materials. In order to improve the mixing performance of the putty, the viscosity of these products must be low. Even when the machine is used to mix heavy bodies, the stress for release is limited by the technical properties of the machine. Even when so-called soft putty or heavy body is used with low viscosity silicone, the high yield stress and high stress viscosity of the light body do not allow sufficient pressure to be generated by the uncured soft putty or heavy putty during impression acquisition. The problem arises because it is possible. Therefore, flow in details in the product is not guaranteed. This problem is more pronounced when the low viscosity material has a high yield stress.

[0012] In addition, hydrophilic components that improve the wetting properties of silicones tend to create new problems. This problem is a problem of the stability of the crosslinked SiH component to wetting, since these functional groups are particularly susceptible to hydrolysis reactions under basic conditions. Thus, water-absorbing inorganic fillers such as calcium sulfate hemihydrate,
The addition of anhydrous calcium sulfate, calcium chloride and the like and adsorbing compounds such as zeolites, molecular sieves, and other similar adsorbing and absorbing compounds is a preferred embodiment of the present invention.

It is known in the art that low viscosity can be achieved with short-chain dimethylvinylsilyl-terminated polydimethylsiloxanes with or without the addition of low filler content. These materials usually have only very low mechanical strength, such as low tear strength, which is too weak for use as a dental impression material. At very low viscosities, the material tends to drip from the teeth and the filler separates after a period of time.

In summary, polysiloxane impression materials provide sufficient working time, tear strength and wettability to improve and use these compositions for taking oral hard and soft tissue impressions. However, it is still necessary to improve viscosity, tear strength and wettability.

SUMMARY OF THE INVENTION The novel polyvinylsiloxane impression materials are useful in low and high viscosity impression compositions for recording hard and soft tissues in the oral cavity. The novel impression material is a platinum catalyzed vinyl polysiloxane material, preferably a two-component polymerizable organosiloxane composition. One component comprises a catalyst for polymerization and comprises: (a) a QM resin containing vinyl groups, (b) a dispersion having a vinyl content of about 0.16 to 0.24 mmol / g. The QM
A vinyl-terminated linear polydimethylsiloxane fluid formed with a resin;
(C) an organohydrogenpolysiloxane for cross-linking the vinyl group, (d) an organoplatinum catalyst complex for accelerating the polymerization of the component, (e) an amount sufficient to temporarily delay the initiation of the polymerization. A retarder component, (f) a filler, and (g) a surfactant that imparts wetting to the composition, wherein the surface contact angle of the composition to water after 3 minutes is less than 50 °.

Preferably, the dispersions of (a) and (b) have a viscosity of about 5,000 to 60,000 cps. The dispersions of (a) and (b) may comprise a plurality of dispersion components having the desired viscosity and QM resin content. Preferably, the QM resin-containing dispersion comprises a first dispersion component having a viscosity of about 5,000 to 7000 cps and a second dispersion component having a viscosity of about 45,000 to 60,000 cps, wherein the QM resin comprises about 2 to about 2 cps of each dispersion.
Contain from 0 to 25% by weight.

[0017] Suitable QM resin _comprises a polyorganosiloxane comprising units of _{SiO 4/2} and ^R 1 ^R ₂ 2 _{SiO 1/2} units. Here, R ¹ is unsaturated, preferably vinyl, and R ² is alkyl, aryl, such as methyl, ethyl, phenyl and the like. More preferably, the QM resin comprises the formula:

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The retarder component of the composition is a low molecular weight vinyl functional fluid that is a linear or cyclic polysiloxane in an amount of at least about 0.030% by weight of the composition. Preferably, the retarder component comprises fluid 1,3-divinyl, tetramethyldisiloxane in an amount of 0.030 to 0.12% by weight of the composition.

The filler component of the present invention comprises from about 15 to about 45% by weight of the composition, and
Preferably, it contains about 20 to about 40% by weight of the filler mixture.

The major components of the composition of the present invention are surfactants for providing wetting, preferably comprising an HLB of about 8-11 and a pH of about 6-8. The most preferred surfactant is a nonionic surfactant, nonylphenoxypoly (ethyleneoxy) ethanol, having an HLB of about 10.8.

For relatively high viscosity compositions of the present invention, the compositions include an emulsifying plasticizer that provides the catalyst complex with the desired handling and flow properties, and adds to those of the second component. Harmonize. There, a suitable composition for taking a dental impression would be conveniently formed. Preferably, the plasticizer comprises alkyl phthalate at about 0.5 to 2.0% by weight of the catalyst component, and most preferably is octylbenzyl phthalate.

After polymerization, the composition of the present invention is 270 to 300 PSI (1.86 to 2.06
MPa) and a contact angle of less than about 50 ° after 3 minutes with water. For the lower viscosity impression material of the present invention, the tear strength will be somewhat lower than about 200 PSI (1.38 MPa), which is still substantially improved from the prior art.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The polymerizable polysiloxane compositions of the present invention generally comprise an organopolysiloxane having at least about 2 vinyl groups per molecule, and further comprising dispersed therein a molecular polysiloxane. Organic hydrogen polysiloxane having at least about two hydrogen atoms bonded to at least two silicon atoms per molecule, a catalyst for promoting the addition of silicon atoms bonded to the hydrogen atoms to polysiloxane vinyl groups, filler, initiation of polymerization A low molecular weight retarder composition for delaying the emulsification, and a surfactant for emulsification that imparts wetting to the impression material.

The composition of the present invention is preferably divided into two components. The first component (although it is conveniently referred to as the "base paste") comprises a vinyl organopolysiloxane dispersion, an organohydrogenpolysiloxane, the surfactant, and a portion of the filler. The second part of the two-component composition is called the "catalyst paste" and comprises the second part of the vinyl polysiloxane, a catalyst to accelerate the addition reaction, during polymerization and usually released during the polymerization. With additional exhaust reagents, pigments and fillers for the hydrogen.
If a high viscosity impression material is desired, an emulsifying plasticizer may be added to the catalyst paste so that the working viscosities of the two components are compatible and have the desired flow characteristics. A wide variety of organopolysiloxanes having at least about 2 vinyl groups per molecule are known as inclusions in the dental polysiloxane compositions of the present invention to form dispersions including tetrafunctional vinyl polysiloxanes. . Each of these materials may be included to a greater or lesser extent depending on the practice of the invention.
Preferred for use herein are vinyl terminated linear polydivinylsiloxanes, preferably divinylpolydimethylsiloxane. Such polymers are solids having various average molecular weights with concomitant variations in viscosity. These materials are desirably selected to have a viscosity appropriate for the conditions encountered by the resulting silicon material.

The dispersions of interest have a viscosity range from 5000 to 60000 cps. As a practical matter, employing mixtures of dispersed polymers having different viscosities and physical properties is advantageous to provide compositions having the desired thixotropic properties and viscosities.

The dispersion of interest is formed in two viscosity ranges: (1) a first dispersion having a viscosity of about 5000 to 7000 cps, and (2) a second dispersion having a viscosity of about 45000 to 65000 cps. Preferably. While it is advantageous to provide a polysiloxane oligomer for this purpose that has a methyl substituent, other substituents may also be included in the composition according to the present invention. Thus, alkyl, aryl, halogen and other substituents may be included to a greater or lesser extent as useful vinylpolysiloxane moieties. Those skilled in the art will be able to determine from the above discussion which polysiloxane materials are suitable for a particular utility.

[0027] The tetrafunctional polysiloxane, selected and known in the art as a QM resin, has improved tear strength for polymerized impression compositions by increasing its resulting polymerized crosslink density. Supply. As is known, the QM resin is tetrafunctional _{SiO 4/2} of Q units, ^{_{and, R 1 R 2 2 SiO 1/2}} ( wherein ^{R 1} is one of unsaturated, preferably vinyl, R ² is an alkyl, aryl or the like such as methyl, ethyl or phenyl). In a preferred composition, R ¹ is vinyl and both R ² are methyl. The most preferred composition has the formula:

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The QM resin defines a vinyl concentration in the dispersion of the vinyl terminated polydivinylsiloxane of at least about 0.16 mmol / g. Preferably, the vinyl concentration is between 0.16 and 0.24 mmol / g. The amount of QM resin is preferably about 20 to 25% by weight of the dispersion. Such dispersions are marketed by Bayer Corp., Silicon Division, Pittsburgh, PA. Other QM resin formers may be used, including those that are free of admixture or dispersed in a medium other than the suitable fluidic polydivinylsiloxane.

A key element of the present invention is a retarder that delays the onset of polymerization of the QM resin / dispersion so as to provide sufficient working time to use the composition. This retarder slows down the polymerization that would otherwise be too fast as it is consumed. A preferred retarder liquid in the preferred impression material of interest is 1,3 divinyltetramethyldisiloxane at a concentration sufficient for retardation. This concentration is at least about 0.03 of the composition.
%, Preferably about 0.03-0.12% by weight. This preferred amount is 0.0015 which is a typical amount used in PVS systems for stabilizing the composition.
In contrast to amounts as low as -0.020% by weight. In addition, any substance having a low molecular weight vinyl functional group that is first consumed during polymerization and delays curing appropriately and as desired, such as linear and cyclic polysiloxanes, are suitable as retarders.

[0030] Organohydrogenpolysiloxanes useful in the practice of the present invention are well known to those skilled in the art. However, it is necessary to use polysiloxanes in which hydrogen atoms are directly bonded to silicon atoms, and that they have appropriate viscosity and other physical properties.
Alkyl (especially methyl), aryl, halogen and the like can also be used as substituents in the molecule. It is only necessary that such substituents do not interfere with the platinum-catalyzed addition reaction. It is preferred that the molecules used have at least two silicon-bonded hydrogens per molecule. Polymethyl hydrogen siloxane is preferred because of its viscosity in the range of about 35-45 cps.

[0031] Catalysts useful for catalyzing the reaction of the silicon atoms (bonded to hydrogen) with the vinyl groups of the vinyl polysiloxane molecule are preferably platinum-based. In this regard, it is preferred to use a platinum compound such as chloroplatinic acid, preferably as a mixture or complex with one or more vinyl compounds, especially vinyl polysiloxanes. While it is known that such compounds are preferred, other catalysts are also useful. Noble metals such as metallic platinum (platinum), palladium, rhodium, and their respective complexes and salts are also useful. In view of toxicological tolerance, platinum is highly preferred for dental applications.

[0032] The compositions of the present invention also include a filler, preferably a hydrophobic filler. Siri
Mosquito, alumina, magnesia, titania, inorganic salts, metal oxides, glass, etc.
A variety of inorganic hydrophobic fillers can be used. According to the present invention, silicon dioxide
It has been found preferable to use mixtures. These silicon dioxides
Is crystalline silicon dioxide, such as powdered quartz (4-6μ); diatomaceous earth (4-6μ)
Such amorphous silicon dioxide; Cab-b-Sil TS-530 (Cabot, 160-240 m)
²/ G) obtained from silanized fumed silica. the above
The size and surface area of the material will determine the viscosity and thixotropy of the resulting composition.
Controlled to control. All or some of the above hydrophobic fillers are
As is well known to those skilled in the art, silanizing or "keying"
Surface treatment. It can be silanized using known halogenated silanes or silazides.
The filler is preferably present from about 15 to about 45% by weight of the composition to provide a polymeric rich
To form an impression composition with improved flow properties. These fillers are
More preferably, it is present at about 35-40% by weight.

A preferred filler mixture for higher viscosity formulations comprises 14-24% by weight crystalline silicon dioxide and 3-6% by weight amorphous silicon dioxide, 4-8% by weight silanized fume silicon dioxide. The most preferred filler is about 19% cristobalite having a particle size of about 4-6μ, about 4% of diatomaceous earth having a particle size of about 4-7μ, and a surface area of about 16%.
Fumed silica 0-240m ² / g is approximately 6%.

A chemical system can be used to reduce the presence or extent of hydrogen gas emissions that may result from vinyl polymerization. Thus, the composition may include a refined version of platinum that seeks and incorporates such hydrogen. Platinum may be deposited on a salt that is substantially insoluble and has a surface area between about 0.1 and 40 m ² / g.
Suitable salts are barium sulfate, barium carbonate, calcium carbonate of suitable particle size. Other substrates include diatomaceous earth, activated alumina, activated carbon, and the like. Inorganic salts,
It is particularly preferred in that it imparts stability to the resulting material containing them. Platinum dispersed on the salt is about 0.2 to 2 ppm based on the weight of the catalyst component. The use of platinum dispersed on inorganic salt particles has been found to substantially eliminate or reduce the release of hydrogen gas during the curing of dental silicone.

An important improvement of the present invention is the inclusion of a surfactant in the composition that imparts wettability to the composition. This wettability is indicated by a surface contact angle with water of less than 50 ° for 3 minutes. One of the unexpected effects of the choice of surfactant is that a wetting contact angle of less than 50 degrees is achieved within about 2 minutes and decreases throughout the working time of the composition, always with less than 50 degrees. Is to provide a great clinical advantage. This is in contrast to prior art polyvinyl siloxane and surfactant formulations, which take longer to completely wet. This high wetting rate of the composition of the invention as shown in the figure is particularly advantageous during the impression taking process.

In FIG. 1, the wet contact angle expressed in degrees as a function of time (minutes) is compared between the polyvinylsiloxane composition of the present invention and the composition of the prior art. Curve A shows that the composition of the present invention has a wet contact angle of about 50 degrees 2 minutes after mixing the base and catalyst components. FIG. 1 shows that good wettability is achieved early and further increases at a fast rate over about 3.3 minutes, the effective working life of the impression agent. Curves B and C are prior art polyether impression materials and polyvinylsiloxane impression materials, respectively. FIG. 2 shows the viscosity of the impression material as a function of time for the composition of the invention (curve A) and for the composition of the prior art described above (curves B and C). FIG. 2 shows the progress of the polymerization process after mixing, and together with FIG. 1 shows that the increase in wettability of the composition of the present invention occurs during the critical working time of the impression material.
This is a significant advantage over other known systems.

[0037] The surfactants of the present invention can be cationic, anionic, amphoteric, or non-ionic. The main criterion for selection is the hydrophobic-lipophilic balance (Hydrophobic
Lipophilic Balance (HLB) value by Gower "Handbook of Industrial Surfact
ants "(see 1993) must be in the range of 8-11. As is well known, the higher the HLB value, the more hydrophobic the material.
In addition, the pH of the surfactant must be in the range of 6-8 to prevent side reactions that may be detrimental to the polymerization of the impression material. A preferred surfactant is nonionic, consisting of nonylphenoxypoly (ethyleneoxy) ethanol having an HLB value of 10.8, and is marketed by Rhone-Poulenc of Cranbury (NJ) as Igepal CO-530. Compared to Bryan et al., U.S. Pat.
The B value is 13.0 and the structure is different from that of CO-530 (the number of repetitions of C-530 is 6 and the number of repetitions of C630 is 9). Igepal CO630 has no effect. This indicates the importance of HLB. The amount of surfactant used to make the composition hydrophilic is based on the wetting rate. The desired contact angle at 3 minutes is less than 50 degrees. The compositions of the present invention may include a plasticizer for high viscosity materials. This plasticizer beneficially alters the handling and flow properties of the impression material, especially the catalyst component. One preferred emulsifying plasticizer is octylbenzyl phthalate. Other phthalates are also useful. Plasticizers are not required for low viscosity wash-type impression materials.

The dispersion viscosity of the QM resin is selected according to the desired overall impression material properties. In order to obtain high viscosity handling characteristics, a large amount of 60,000 cps is used. The low viscosity type increases the fluidity by using a lot of 6,000 cps components. The use of a large amount of filler having a small surface area such as cristobalite increases the fluidity of a low-viscosity type impression material. If a large amount of filler having a large surface area such as diatomaceous earth is used, the fluidity of the high-viscosity type impression material is reduced, and the density is increased. The use of emulsifying plasticizers increases the thixotropy of the composition, which is useful for high viscosity materials. However, plasticizers are not usually used in low viscosity materials because high flow is desirable.

The composition of the present invention may contain various pigments to obtain a preferred color. Such pigments are well known and include titanium dioxide and the like.

The two-component composition prepared according to the present invention is used in the same way as conventional impression materials are used. Thus, approximately equal amounts of the base paste and the catalyst paste are mixed well and pressed into the oral cavity or other location for a time sufficient for the composition to polymerize or cure. Once the composition is substantially hardened, it is removed from the mouth or other surface and used to make molds and the like. Subsequently, the shape of the casting surface is formed from the mold and the like.

As will be appreciated by those skilled in the art, it is important that the dental silicone material be capable of being stored at a reasonable storage temperature for an extended period of time in order to maximize its commercial utility. Therefore, it is necessary that such a material does not cause a decrease in physical properties during storage or a substantial change in working time or curing time. In this regard,
Accelerated storage tests using high ambient temperatures can now measure the storage stability of such materials.

Hereinafter, some embodiments of the present invention will be described. Many other compositions could be made within the contemplation of the present invention. The following examples are not limiting and are provided for illustrative purposes.

Example 1 A two-component composition of the present invention is blended with a base paste and a catalyst paste. Double planetary mixer having a mixing tank heated using circulating water at 45 ° C to 50 ° C (double planetar)
y mixer) to mix each component material under 65 mm mercury vacuum. Base paste component In preparing the base paste, first charge all of the organohydrogenpolysiloxane into the mixing tank, and then charge the QM dispersion and filler components and continue mixing until the mixture is uniform . The final base paste is discharged into a storage container. Catalyst paste components Catalyst paste components are compounded and mixed under various conditions and in the equipment described above. Add the platinum catalyst, 1,3-divinyldimethyldisiloxane, QM resin dispersion, filler and pigment to the mixing tank and mix until a homogeneously mixed mass is obtained. Next, the catalyst paste thus mixed is discharged into the storage container. The composition of each component is shown in the table below. Here, each amount is shown by weight percent of each component. Base Catalyst organohydrogenpolysiloxane 9.00 0.00 (5000-7000cps) QM resin dispersion 19.62 23.95 (45000-60000cps) QM resin dispersion 34.59 42.89 Cristobalite 19.01 19.06 diatomaceous earth 6.53 6.41 Cab-O-Sil TS -530 6.53 6.00 Jibinirupori Pigment dispersion in siloxane 0.65 0.25 Titanium oxide pigment 0.07 0.07 Surfactant (Igepal CO-530) 4.00 0.00 Plasticizer 0.00 0.50 Platinum catalyst 0.00 0.64 1,3-Divinyldimethyldisiloxane 0.00 0.07 Finely ground platinum metal on calcium carbonate 0.00 0.16 100.00 100.00

Example 2 First, a two-component composition was prepared by preparing a base paste having the composition shown in the following table, as described in Example 1, and then preparing a catalyst paste. Prepare. Base Catalyst organohydrogenpolysiloxane 9.00 0.00 (5000-7000cps) QM resin dispersion 20.18 31.71 (45000-60000cps) QM resin dispersion 35.61 35.23 Cristobalite 19.74 20.67 diatomaceous earth 4.30 4.28 Cab-O-Sil TS -530 6.45 6.42 Jibinirupori Pigment dispersion in siloxane 0.65 0.25 Titanium oxide pigment 0.07 0.07 Surfactant (Igepal CO-530) 4.00 0.00 Plasticizer 0.00 0.50 Platinum catalyst 0.00 0.64 1,3-Divinyldimethyldisiloxane 0.00 0.07 Finely ground platinum metal on calcium carbonate 0.00 0.16 100.00 100.00

Example 3 First, as described in Example 1, a base paste having the composition shown in the table below was prepared, and then a catalyst paste was prepared.
A component composition is prepared. Base Catalyst organohydrogenpolysiloxane 10.00 0.00 (5000-7000cps) QM resin dispersion 14.73 26.91 (45000-60000cps) QM resin dispersion 43.80 43.80 Cristobalite 17.00 17.40 diatomaceous earth 5.00 5.00 Cab-O-Sil TS -530 5.00 5.00 Jibinirupori Pigment dispersion in siloxane 0.40 0.50 Titanium oxide pigment 0.07 0.07 Surfactant (Igepal CO-530) 4.00 0.00 Plasticizer 0.00 0.50 Platinum catalyst 0.00 0.65 1,3-Divinyldimethyldisiloxane 0.00 0.07 Finely ground platinum metal on calcium carbonate 0.00 0.10 100.00 100.00

Example 4 First, as described in Example 1, a base paste having the composition shown in the table below was prepared, and then a catalyst paste was prepared, whereby the two components of the present invention were prepared. A system composition is prepared. Base Catalyst organohydrogenpolysiloxane 10.00 0.00 (5000-7000cps) QM resin dispersion 19.40 32.37 (45000-60000cps) QM resin dispersion 36.03 36.03 Cristobalite 20.00 20.00 diatomaceous earth 5.00 5.00 Cab-O-Sil TS -530 5.00 5.00 Jibinirupori Pigment dispersion in siloxane 1.50 0.00 Titanium oxide pigment 0.07 0.07 Surfactant (Igepal CO-530) 3.00 0.00 Plasticizer 0.00 0.50 Platinum catalyst 0.00 1.00 1,3-Divinyldimethyldisiloxane 0.00 0.03 Finely ground platinum metal on calcium carbonate 0.00 0.00 100.00 100.00

Example 5 First, as described in Example 1, a base paste having the composition shown in the table below was prepared, and then a catalyst paste was prepared.
A component composition is prepared. Base Catalyst organohydrogenpolysiloxane 11.00 0.00 (5000-7000cps) QM resin dispersion 14.36 28.44 (45000-60000cps) QM resin dispersion 43.07 42.64 Cristobalite 17.00 17.19 diatomaceous earth 5.00 4.95 Cab-O-Sil TS -530 5.00 4.95 Jibinirupori Pigment dispersion in siloxane 1.50 0.00 Titanium oxide pigment 0.07 0.07 Surfactant (Igepal CO-530) 3.00 0.00 Plasticizer 0.00 0.49 Platinum catalyst 0.00 1.13 1,3-Divinyldimethyldisiloxane 0.00 0.06 Finely ground platinum metal on calcium carbonate 0.00 0.09 100.00 100.00

Example 6 First, as described in Example 1, a base paste having the composition shown in the table below was prepared, and then a catalyst paste was prepared.
A component composition is prepared. Base Catalyst organohydrogenpolysiloxane 9.52 0.00 (5000-7000cps) QM resin dispersion 11.19 27.91 (45000-60000cps) QM resin dispersion 38.07 38.21 Cristobalite 22.84 21.21 diatomaceous earth 5.71 5.73 Cab-O-Sil TS -530 5.71 5.73 Jibinirupori Pigment dispersion in siloxane 1.58 0.00 Titanium oxide pigment 0.13 0.13 Surfactant (Tergitol 15-S-3) 4.76 0.00 Plasticizer 0.48 0.48 Platinum catalyst 0.00 0.48 1,3-divinyldimethyldisiloxane 0.00 0.05 Fine grinding on calcium carbonate Platinum metal 0.00 0.08 100.00 100.00

Example 7 First, as described in Example 1, a base paste having the composition shown in the table below was prepared, and then a catalyst paste was prepared.
A component composition is prepared. Base Catalyst organohydrogenpolysiloxane 9.52 0.00 (5000-7000cps) QM resin dispersion 11.19 27.91 (45000-60000cps) QM resin dispersion 38.07 38.21 Cristobalite 22.84 21.21 diatomaceous earth 5.71 5.73 Cab-O-Sil TS -530 5.71 5.73 Jibinirupori Pigment dispersion in siloxane 1.58 0.00 Titanium oxide pigment 0.13 0.13 Surfactant (Igepal CO-630) 4.76 0.00 Plasticizer 0.48 0.48 Platinum catalyst 0.00 0.48 1,3-Divinyldimethyldisiloxane 0.00 0.05 Finely ground platinum metal on calcium carbonate 0.00 0.08 100.00 100.00

Example 8 First, a two-component composition of the present invention was prepared by preparing a base paste having the composition shown in the table below and then a catalyst paste as described in Example 1. Is prepared. Base Catalyst organohydrogenpolysiloxane 9.52 0.00 (5000-7000cps) QM resin dispersion 11.19 27.91 (45000-60000cps) QM resin dispersion 38.07 38.21 Cristobalite 22.84 21.21 diatomaceous earth 5.71 5.73 Cab-O-Sil TS -530 5.71 5.73 Jibinirupori Pigment dispersion in siloxane 1.58 0.00 Titanium oxide pigment 0.13 0.13 Surfactant (Igepal CO-210) 4.76 0.00 Plasticizer 0.48 0.48 Platinum catalyst 0.00 0.48 1,3-divinyldimethyldisiloxane 0.00 0.05 Finely ground platinum metal on calcium carbonate 0.00 0.08 100.00 100.00

Example 9 First, as described in Example 1, a base paste having the composition shown in the table below was prepared, and then a catalyst paste was prepared.
A component composition is prepared. Base Catalyst organohydrogenpolysiloxane 9.52 0.00 (5000-7000cps) QM resin dispersion 11.19 27.91 (45000-60000cps) QM resin dispersion 38.07 38.21 Cristobalite 22.84 21.21 diatomaceous earth 5.71 5.73 Cab-O-Sil TS -530 5.71 5.73 Jibinirupori Pigment dispersion in siloxane 1.58 0.00 Titanium oxide pigment 0.13 0.13 Surfactant (Igepal CO-430) 4.76 0.00 Plasticizer 0.48 0.48 Platinum catalyst 0.00 0.48 1,3-Divinyldimethyldisiloxane 0.00 0.05 Finely ground platinum metal on calcium carbonate 0.00 0.08 100.00 100.00

Example 10 First, as described in Example 1, a base paste having the composition shown in the table below was prepared, and then a catalyst paste was prepared, whereby the two-component system of the present invention was prepared. Prepare the composition. Base Catalyst organohydrogenpolysiloxane 9.52 0.00 (5000-7000cps) QM resin dispersion 11.19 27.91 (45000-60000cps) QM resin dispersion 38.07 38.21 Cristobalite 22.84 21.21 diatomaceous earth 5.71 5.73 Cab-O-Sil TS -530 5.71 5.73 Jibinirupori Pigment dispersion in siloxane 1.58 0.00 Titanium oxide pigment 0.13 0.13 Surfactant (Igepal CO-530) 4.76 0.00 Plasticizer 0.48 0.48 Platinum catalyst 0.00 0.48 1,3-Divinyldimethyldisiloxane 0.00 0.05 Finely ground platinum metal on calcium carbonate 0.00 0.08 100.00 100.00

Example 11 10 g of a representative sample of each of the above examples was mixed in equal parts and the properties of the mixture and the resulting polymer composition were tested. The table below shows the results of the measurements. The first five properties shown were tested according to ADA Standard 19 (Non-Elastomer Impression Materials (1976; as modified in 19a of 1982)). The following methods were used to provide the tensile tear strength, elongation (%) and modulus of the examples. Equal parts of the base component and the catalyst component are mixed and the sample or specimen is cast into a specimen mold (1.5 mm thick, 20 mm × 11 mm, 8 mm deep top arm and a central I part with an I-shaped cavity with 5 mm width) ). The filled mold is clamped between two stainless steel plates and the assembly is placed in a 32 ° C. water bath. Six minutes after the start of mixing, the assembly is removed from the bath. The mold is released from the fixture, the specimen is removed from the mold, and all burrs are removed from the specimen. 10 minutes after the start of mixing,
Secure to the Instron Model 1123 test specimen test grip in elongation mode. That Inst
The ron is attached to a Microcon II microprocessor programmed to calculate tear strength [psi], elongation (%) and modulus. At 11 minutes, the specimen is stressed by Instron at a rate of 10 mm / min until peak failure is reached. (
Set the maximum load to 5 kg. After repeating this for five specimens,
The statistical evaluation results as shown in Table I are shown. The wetting contact angle was measured for each example as follows. Combine 1 g of base and 1 g of catalyst paste together until uniform (about 30 seconds). 0.5 g of the mixed paste is sandwiched between two sheets of polyethylene (Dentsilk) and pressed flat using a 2-3 mm thick glass plate. The specimen is left gently until it cures (about 15 minutes). Remove the polyethylene sheet (be careful not to touch the surface of the specimen), and remove the specimen from the ginometer (g
ynometer) (a well-known device for measuring contact angles). The eyepiece recticle is aligned with the horizontal and vertical planes of the specimen surface and the stopwatch is started while dropping a drop of water on the specimen surface. 1
. From 5 minutes to 3.5 minutes, the internal contact angle (degrees) of the water / specimen interface is measured using a ginometer scale and the specimen is recorded. This record is shown in Table I below.

[Table 1]

Examples 1 to 3 are preferred compositions. Example 1 is suitable for dispensing from a tube and for hand mixing. Example 2 is most preferred for cartridge dispensing and static-mixing. Example 3 describes a composition of the present invention suitable for forming a low viscosity composition suitable for either tube dispensing or cartridge dispensing.

The composition of Example 4 had a high viscosity, exhibited vigorous outgassing, had a high concentration of hydride, and had no outgassing component. Example 5 (with low viscosity) showed good syringe consistency, but high deformation (%) and strain (
%), And the tear strength was low. This composition had a high hydride concentration, low surfactant concentration, low retarder concentration and low catalyst concentration. The compositions of Examples 6, 8 and 9 did not polymerize properly. The composition of Example 6 had too low contents of retarder and catalyst. The surfactant was also too high in HLB and too acidic. The composition of Example 7 lacked wetting ability with a surface contact angle exceeding the desired limit. Examples 8 and 9 both had too low concentrations of retarder and catalyst. The composition of Example 10 exceeded the desired percent deformation.

Example 12 A two-component composition of the present invention (having the composition shown below) is prepared as described in Example 1. The high content of low viscosity QM resin dispersion is utilized to produce low viscosity wash formulations. Also, an additional surfactant is used and no plasticizer is required. Base Catalyst organohydrogenpolysiloxane 8.0 - (5000-7000 cps) QM resin dispersion 28.7 39.6 (45000-60000 cps) QM resin dispersion 12.3 16.7 Cristobalite 32.0 39.6 diatomaceous earth - - Cab-O-Sil TS -530 3 3 Pigment pre-dispersed in divinyl polysiloxane 1-Titanium oxide pigment--Surfactant (Igepal CO-530) 7.5-Plasticizer--Platinum catalyst-0.36 1,3-divinyldimethyl-disiloxane-0.11 On calcium carbonate Platinum fine powder-0.60 Dry calcium sulfate 5.0-Organic pigment 2.5-Total 100.00 100.00

Example 13 Two-component composition (having the composition shown below) is prepared as in Example 1.
The resulting formulation is a low viscosity wash impression material. Base Catalyst organohydrogenpolysiloxane 9.0 0 (5000-7000 cps) QM resin dispersion 13.2 29.6 (45000-60000 cps) QM resin dispersion 47.27 47.27 Cristobalite 14.0 14.0 diatomaceous earth 4 4 Cab-O-Sil TS -530 4 4 Pigment pre-dispersed in divinyl polysiloxane 1-Titanium oxide pigment 0.035 0.035 Surfactant (Igepal CO-530) 5-Plasticizer--Platinum catalyst-0.28 1,3-divinyldimethyl-disiloxane-0.014 on calcium carbonate Platinum fine powder-0.80 Dried calcium sulfate--Organic pigment 2.5-Total 100.00 100.00

Example 14 Two-component composition (having the composition shown below) is prepared as in Example 1.
The resulting formulation is a low viscosity wash impression material. Base Catalyst organohydrogenpolysiloxane 7.5 0 (5000-7000 cps) QM resin dispersion 35.56 44.89 (45000-60000 cps) QM resin dispersion 11.84 14.97 Cristobalite 29 31.63 diatomaceous earth 0 - Cab-O-Sil TS -530 3 3 Pigment pre-dispersed in divinyl polysiloxane 0.9-Titanium oxide pigment--Surfactant (Igepal CO-530) 5-Plasticizer--Platinum catalyst-0.55 1,3-divinyldimethyl-disiloxane-0.056 on calcium carbonate Platinum fine powder-0.5 Dried calcium sulfate-5 Organic pigment 2.2 0 Total 100.00 100.00

Example 15 The test method of Example 11 is applied to a representative sample of the formulations of Examples 12-14. Table II below shows the results of the measurements.

[Table 2]

A dental impression material according to another embodiment of the present invention is a two-component system based on the following addition-cured silicone:

A base paste of about 45 to 55% by weight based on 100% by weight of the dental impression material. The base paste includes: a1 about 1 to about 10% by weight of dimethylvinyl-terminated linear polydimethylsiloxane per 100% by weight of the base paste; a2 about 8 to about 20% by weight of trimethylsilyl- or dimethylhydrosilyl-terminated with respect to 100% by weight of the base paste; A15 to about 25% by weight of 15 to 25% by weight based on 100% by weight of the base paste.
Dimethylvinylsilyl-terminated polydimethylsiloxane containing 100% by weight of a highly dispersed SiO2 containing from about 50 to about 60% by weight of the functional groups and ethoxy groups reactive in the hydrosilylation reaction, based on 100% by weight of the a4 base paste. Optionally included, a
SiO4 / 2, RO1 which is homogeneously soluble in 1 and wherein R represents n-alkyl, phenyl or vinyl and has an alkoxy group content of less than 4 mmol / g
A5 low molecular weight QM resin containing R2 SiO2 and R3SiO1 / 2, a5 a remover that adsorbs water from both components and the surroundings a6 about 0 to about 10% by weight of dimethylvinylsilyl-terminated linear based on 100% by weight of base paste Dimethyl (vinylmethyl) siloxane copolymer, a7 amphoteric surfactant a8 for improving wetting, and optionally pigment.

The impression material further comprises from about 45 to about 55% by weight of a catalyst paste, including: b1 about 1 to about 5% by weight of dimethylvinyl-terminated linear polydimethylsiloxane per 100% by weight of catalyst paste; b2 Altitude of about 30 to about 35% by weight of 20 to 35% by weight with respect to 100% by weight of catalyst paste B) a dimethylvinylsilyl-terminated polydimethylsiloxane containing SiO2 dispersed therein, optionally comprising about 55 to about 70% by weight, based on 100% by weight of the catalyst paste, of functional groups and ethoxy groups reactive in the hydrosilylation reaction. , A1
SiO4 / 2, RO1 /, wherein R represents n-alkyl, phenyl or vinyl and has an alkoxy group content of less than 4 mmol / g
Low molecular weight QM resin containing 2 and R3SiO1 / 2, b0 about 100% by weight of dimethylvinylsilyl-terminated linear dimethyl (vinylmethyl) siloxane copolymer to 100% by weight of catalyst paste, b5 100% by weight of catalyst paste About 0.5 to about 1.5% by weight of H2Pt
Pt catalyst prepared from Cl6 and tetramethyldivinyldisiloxane, b6 short-chain dimethylvinylsilyl-terminated polydimethylsiloxane (n = 0-5), b7 hydrogen sorbent, and optionally b8 pigment.

All “%” and “percent” are by weight. A low-viscosity type dental impression material having flow properties under clinical conditions with high tear strength for maintaining a subgingival undercut is provided. As used herein, "low" viscosity means type 3 according to ISO 4823. These properties are illustrated by the following physical parameters. ^{Viscosity: h [200Pa] = 5.0~15.0Pas h} [200Pa] for a single paste = 15.0～25.0Pas mixed material to and yield stress: θ ^[0~10Pa] about 5. Less than 0 Pa Contact angle: Less than about 45 ° Tear strength: More than about 1.5 MPa

Here, a1 and b1 are a vinyl-terminated dimethylpolysiloxane of the following formula having a viscosity at 20 ° C. in the range of 0.2 to 200 Pas and a vinyl content of 0.01 to 0.5 mval / g. Characterized. "N" represents an integer from 50 to about 1300, which is not an absolute limitation of the present invention.

Embedded image

Component a2 is characterized as an organopolysiloxane of the formula having at least three Si-bonded hydrogen atoms per molecule. Preferably, the organopolysiloxane has from 2.0 to 8.5 mval / g of active SiH units.

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[0066] Components a3 and b2 are characterized as aerosils comprising organopolysiloxanes having dimethylvinylsilyl end groups. The examples are prepared according to DE-A 2,535,334 and are incorporated herein by reference.

Components a4 and b3 are characterized by containing tetrafunctional SiO4 / 2 as the Q moiety and monofunctional R3SiO1 / 2 as the M unit, where R can be alkyl, aryl or alkenyl; Preferably it is methyl or vinyl. Furthermore, it is possible for R2SiO2 / 2 to be present as trifunctional RSiO3 / 2 (silsesquioxane units or T-units) and D units, but the content of these QM units must be greater than about 10%.

Component a5 is selected from water-absorbing inorganic fillers, such as calcium hemihydrate sulfate, anhydrous calcium sulfate calcium chloride, and absorbent compounds such as zeolite-type molecular sieves and other similar absorbent and adsorptive compounds. . Zeolite type A with a content of about 0.5 to about 10% by weight of the base paste is one of the preferred absorbents.

Components a6 and b6 are characterized as the copolymerization reaction products of dimethyldihalogenosilane or dimethyldialkoxysilane with methylvinyldihalogenosilane or methylvinyldialkoxysilane leading to copolymers of the formula

Embedded image

Here, the above R is preferably vinyl which gives a vinyl content of 0.5 to 3.0 mval / g and a viscosity of η (20 ° C.) = 200 mPas to 1000 mPas. One of the preferred R groups is (CH2) 3-O- [CH2CH2-O] x-C
H3, where x is an integer from about 2 to about 10.

Component a7 is characterized as nonylphenoxypolyethyleneoxyethanol, and b5 is characterized as the reaction product of hydrated chloroplatinic acid and tetramethyldivinyldisiloxane.

Component b7 is characterized by highly dispersed platinum or palladium on charcoal, calcium sulfate, alumina or zeolites.

The combination of the components according to the invention has a very high tear strength with high hydrophilicity and good flow and wetting properties.

The combination of the components according to the present invention promotes the reduction of the consistency of both the single paste and the mixture. The base paste according to the invention exhibits Newtonian flow behavior with stress dependent viscosity and thixotropic hardening. Even at high surfactant content (Examples A, B and D below), the yield stress of the base paste derived from the rheological substructure is lower than that of a conventional lightweight formulation (Example F). Is much lower.

The following description will be made with reference to FIGS. 3 and 4 as already outlined. In FIG. 3, the x-axis represents the frequency omega in units of l / sec and the two y
The axis is the tear stress G '(y-axis on the left) in units of Pascal (Pa) and the Pascal second (
Pas) in units of n '(left y-axis). In FIG. 4, x
The axis represents time in seconds (s). The y-axis represents the tear stress G in units of Pa on the left y-axis. On the right y-axis are shown two parameters, namely the viscosity n 'in kPas and the dynamic loss angle. The shear modulus G 'of the fluid system is split into two parts. The storage modulus G 'represents the elasticity of the system, while the loss modulus G "represents the viscosity. The dynamic loss angle, delta, represents the angle between G 'and G "in the triangle formed by axes G' and G".
FIG. 5 has the same x-axis and y-axis as FIG.

Further, in FIG. 3, the letter “A” represents the shear modulus G ′; the letter “B” represents the delta or the dynamic loss angle between G ′ and G ″; n ', ie P
Represents the viscosity in as units. In FIG. 4, the small circle represents delta; the letter "V" in the circle represents viscosity; the asterisk represents shear stress G; the small square represents storage modulus G ';''.

The meaning of each symbol in FIG. 5 is the same as that described with reference to FIG.

The catalyst paste according to the invention exhibits properties close to Newtonian flow properties of a constant viscosity of 10.0 Pas, even at an aerosol content of 10%, showing neither yield stress nor thixotropic effects. The rheological properties of the single paste according to the invention were measured by frequency sweep using a vibration rheometer (CS-50 Fa. Bohlin). FIG. 3 illustrates the difference between the base non-Newtonian flow characteristics and the quasi-Newtonian behavior of the catalyst.

The thixotropy of the base paste according to the invention can be described by a time sweep measured with a vibrating rheometer under unconfined conditions. The sample was placed on the plate of the cone / plate measuring device.
A boost stress of a for 5 seconds disrupted the rheological substructure responsible for yield stress. The relaxation of the elasticity was measured by a frequency of 1 Hz and a forced vibration with a deformation of 0.0005 radians at 10 second intervals. As can be understood from the graph shown in FIG.
At the start of the measurement, the loss modulus (G ″) is higher than the storage modulus (G ′),
The paste acts as a liquid. After a relaxation time of about 600 seconds (sec.), The substructure is reconstructed and the material exhibits elastic behavior. G "compared to typical relaxation times
The gel point where = G 'characterizes the thixotropic behavior of a non-Newtonian fluid.
In the base paste according to the present invention, the time t _g (usm
) Is a minimum of 90 seconds.

Due to the thixotropy of the base paste, the material according to the invention behaves like a liquid, while having a yield stress and a high stress-dependent viscosity, and flows over the surface immediately after mixing by discharge from the cartridge. When the two components are release mixed by a static mixer, the flow behavior is mainly characterized by catalyst paste. The reason is that, immediately after mixing, the rheological substructure in the base paste, which causes the yield stress and the stress-dependent viscosity, is disturbed by the shear stress of the mixing.

The material according to the invention has been preferably developed for use as a dental cartridge material. Due to the rheological properties of the material according to the invention, the material can be released with very little force. Therefore, the material according to the present invention can be discharged from the cartridge using a very small static mixer, so that the waste of the material can be minimized, and the cost can be greatly reduced for the user. In this specification, the meaning of the term "low viscosity" is in accordance with ISO 4823.

To investigate the increase in viscosity during the curing reaction of the material according to the invention, a sample (Example B) was measured by time sweep using a vibrating rheometer (FIG. 5). Material (
Immediately after release from the cartridge (used for dentistry), they were placed on the plate of the cone / plate measurement device and measurements were started 10 seconds after release. Release first viscosity value 15
Recorded after seconds. Measurements were taken at a frequency of 1 Hz, 0.001
Measurements were taken at 10 second measurement intervals due to radian deformation. Under these conditions, the rheological substructure was not disturbed by the oscillating torque (as shown in the amplitude sweep of both single pastes). As shown in FIG. 5, the viscosity increases very rapidly during the first period of the reaction. This effect can be explained by the relaxation of the shear stress caused by ejection from the cartridge (thixotropic hardening). At the beginning of the curing reaction, the dynamic loss angle δ is greater than about 45 °. This means that at this point the material has no yield stress. When dispensed from the cartridge, the material can flow over the blade surface with low shear stress as a liquid even under the influence of gravity.

What is important for the speed of the curing reaction is firstly the gel time t _g (cured material), and secondly the cured time t _c . The gel time t _g (cured material) is determined by the dynamic loss angle δ =
arctan (G "/ G ') is the time to have a maximum. If there is no maximum in the dynamic loss angle (δ> 45 °), the gel time is reduced to a dynamic loss angle of 45 °.
(G ′ = G ″). The curing time is the time at which the storage modulus G ′ reaches a plateau (flat area).

In Examples A and B according to the present invention, the formed network is partially penetrated by the existing network of QM-resin. Thereby, the net strength is improved.
These QM-resins have a tetrafunctional SiO _4/2 as the Q-site and a monofunctional R ₃ SiO _1/2 as the M-unit, where R is alkyl, aryl or alkenyl, most preferably methyl or vinyl. (Can be). Moreover, trifunctional _{RSiO 3/2} as D- units (silsesquioxane or T- units) and _R 2 _{SiO 2/2} may also be present. The content of these QM-resins is preferably higher than about 10%.
With a low content stream as in the case of Example E, the tear strength cannot be sufficiently improved.

Instead of using a high QM-resin content as in Examples A and B, a high functionality vinyl-silicone is used in Example D. In this material according to the invention, a high tear strength results from the presence of a high content of reactive vinyl groups in both components. In conventional additive curable silicones, these functional groups are only present at the ends of the long-chain polydimethylsiloxane. In the materials according to the invention, additional vinyl groups are present on the chains of these polymers. These additional functional groups provide high network density with enhanced mechanical strength.

In the case of the material according to the invention, it is not necessary to add a filler to reinforce the mechanical strength. The use of fillers is only needed to adjust the flow properties and to absorb moisture from the surfactant or environment. Even with a filler content of less than 15% by weight, the materials according to the invention (Examples A, B and D) have a higher tear strength than conventional high-filled lightweight bodies (filler content higher than 40% by weight, Example F). Have. In combination with high compressive strain, this increased mechanical strength can maintain subgingival undercuts.

The material according to the present invention was added with a large amount of a surfactant in order to improve the wettability, so that the contact angle with water was made very small. This surfactant is the same as described above. Surprisingly, these high amounts of surfactant gave very low yield stresses of less than 5 Pa for the base pastes (Examples A, B and D).
The conventional lightweight body (Example E) had a higher yield stress even at a lower surfactant content. As can be seen from FIG. 3, this low yield stress of the base paste does not lead to the yield stress of the poured material. It is provided by a rheological infrastructure disturbed by shear stress during ejection from the cartridge.

In another embodiment of the present invention, an impression material is provided, but includes QM-resin for higher cross-linking and improved tear strength. In addition, surfactants,
For example, Igepal CO-530 is provided to improve wetting. These improvements lead to a direct improvement in the impression details and also to a lower tear of the impression material. The impression material has the consistency and final stiffness of the cured material and is preferred for high viscosity tray impression materials. As explained below,
The impression material may have either fast or normal (relatively slow) curing properties. Table A below shows examples of base materials, examples of fast cure, and examples of normal cure.
It is understood that the amount of each material may vary over a range of up to about 99% or may be greater than the amount provided. Table B gives a comparative example.

[Table 3]

[Table 4]

Other examples of materials of the present invention include the following weight percent components:

[Table 5]

In Table C, the notations MONOPHASE, LV-RS, LV-FS, XLV
-RS, XLV-FS, RIGID-RS and RIGID-FS give an indication as to the viscosity of the composition and the setting time. The "MONOPHASE" product is a useful material for both tray and syringe type applications. LV-RS is a low viscosity normal cure product and LV-FS is a low viscosity fast cure product. XLV
-RS and XLV-FS have ultra-low viscosities and are of normal cure and fast cure respectively. RIGID-RS and RIGID-FS are normal cure and fast cure compositions, respectively, and are compositions having greater viscosities than the other compositions in Table C. These terms are related to each other by low viscosity and "cure".

[0091] When dry calcium sulfate is present in the base paste portion of the composition, it improves the stability of the base paste.

A preferred range of such components, according to the present invention, is as follows.

[Table 6]

Further Examples (All percentages are by weight)

[0094] Example A component A: 53.0% QM-resin containing dimethylvinylsiloxy-terminated polydimethylsiloxane 20.0% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 5.0% crosslinking H- silicon (SiH content 7.5 mval / g) 10.0% Chain-extended H-silicon (SiH content 2.6 mval / g) 5.0% Zeolite type A 0.5% Titanium dioxide 6.5% Surfactant (nonylphenoxypolyethylene) oxy ethanol) component B: 66.5% QM- resin containing dimethylvinylsiloxy-terminated polydimethylsiloxane 32.68% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 0.5% Pt-Catalyst 0.05% divinyl tetramethyl disiloxane 0.07% Pt / CaCO 0.20% pigment

[0095] Example B component A: 53.0% QM- resin containing dimethylvinylsiloxy-terminated polydimethylsiloxane 20.0% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 15.0% crosslinking H- silicon (SiH content 4.3 mval / g) 5.0% Zeolite type A 0.5% Titanium dioxide 6.5% Surfactant (nonylphenoxypolyethyleneoxyethanol) Component B: 66.5% QM-resin-containing dimethylvinyl-terminated polydimethyl siloxane 32.68% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 0.5% Pt-Catalyst 0.05% divinyl 0.07% tetramethyl disiloxane _Pt / CaCO 3 0.20% pigment

[0096] Example C component A: 16.5% dimethylvinyl terminated polydimethylsiloxane 30.0% QM-resin containing dimethylvinylsiloxy-terminated polydimethylsiloxane 20.0% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 15. 0% Cross-linked H-silicon (SiH content 4.3 mval / g) 5.0% Zeolite type A 0.5% Titanium dioxide 6.0% Surfactant (nonylphenoxypolyethyleneoxyethanol) 6.5% Hydrophilicity modifiers (Fa.Wacker) component B: 36.1% dimethylvinyl terminated polydimethylsiloxane 30.0% QM-resin containing dimethylvinylsiloxy-terminated polydimethylsiloxane 32.68% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 0.5% 0.4% t-Catalyst short dimethylvinyl terminated polydimethyl - (vinyl methyl) - siloxane 0.07% _Pt / CaCO 3 0.43% pigment

[0097] Example D component A: 33.5% dimethylvinyl terminated polydimethylsiloxane 15.0% QM-resin containing dimethylvinylsiloxy-terminated polydimethylsiloxane 22.50% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 11. 0% Cross-linked H-silicon (SiH content 7.5 mval / g) 6.0% Dimethylvinyl-terminated dimethyl- (methylvinyl) -siloxane copolymer (viscosity 5.0 Pas) 5.0% Zeolite type A 1.0% D Titanium oxide 6.0% Surfactant (nonylphenoxypolyethyleneoxyethanol) 0.2% Spearmint oil Component B: 54.03% Dimethylvinyl-terminated polydimethylsiloxane 10.0% QM-resin-containing dimethylvinyl-terminated polydimethylsiloxa 32.90% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 1.0% Pt-Catalyst 0.10% divinyltetramethyldisiloxane 1.0% dimethylvinyl terminated dimethyl - (methylvinyl) - siloxane copolymer (viscosity 0.2 Pas) 0.07% Pt / CaCO ₃ 0.40% pigment

[0098] Example E component A: 44.6% dimethylvinyl terminated polydimethylsiloxane 10.0% QM-resin containing dimethylvinylsiloxy-terminated polydimethylsiloxane 20.0% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 15. 0% Crosslinked H-silicon (SiH content 4.3 mval / g) 5.0% Zeolite type A 0.2% Titanium dioxide 5.0% Surfactant (nonylphenoxypolyethyleneoxyethanol) 0.2% Spearmint oil component B: 57.25% dimethylvinyl terminated polydimethylsiloxane 10.0% methyl silsesquisiloxanes resin containing dimethylvinylsiloxy-terminated polydimethylsiloxane 32.00% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 0. 4% Pt-catalyst 0.03% Divinyltetramethylsiloxane 0.07% Pt / CaCO ₃ 0.25% Pigment

Example F Component A: 39.1% dimethylvinyl terminated polydimethylsiloxane 10.0% highly dispersed SiO ₂ -containing dimethylvinyl terminated polydimethylsiloxane 8.4% crosslinked H-silicon (SiH content 4.3 mval / g) 5.0% calcium sulfate hemihydrate 7.0% diatomaceous earth 25.0% quartz powder 0.2% titanium dioxide 0.2% spearmint oil 0.11% pigment 5.0% surfactant (nonyl phenoxy polyethylene oxy ethanol) component B: 51.0% dimethylvinyl terminated polydimethylsiloxane 10.0% highly dispersed SiO ₂ containing dimethylvinyl terminated polydimethylsiloxane 7.0% diatomaceous earth 29.25% quartz powder 2.0% plasticizer 0.4% Pt-catalyst 0.03% divinyltetramethyl Siloxane 0.07% Pt _/ CaCO 3 1.0% titanium dioxide

The rheological parameters of the examples of the present invention were determined as follows. The rheological properties of a system consisting of an insoluble solid filler and two or more immiscible liquid phases are:
It is characterized by a rheological substructure as micelles formed by surfactants and filler particles. Therefore, the viscosity of these systems, especially emulsions, is highly dependent on shear stress. For single pastes and mixtures, viscosities were measured in a 200 Pa shear stress creep test. A rotation mode vibration / rotational rheometer (CS-50Fa, Bohlin) was used as the measuring device. What is important in this parameter is that measurement is performed under a constant flow rate condition. Otherwise, the measurements will lack physical validity. A shear stress of 200 Pa is much higher than the yield stress of the base paste of the present invention. The rheological substructure of the paste is inhibited under these conditions. Under non-destructive conditions, especially the viscosity of the base paste is very high.

In the surfactant-containing paste (base paste), the rheological substructure is formed by the dipolar molecules of the surfactant. At stresses below the yield stress, these micelles form a solid structure with the filler. The system behaves quasi-elastically by a linear shear stress / strain modulus relationship. If the shear stress increases and the viscosity of the material reaches a maximum and exceeds the yield stress, the substructure is disturbed and the system behaves as a non-Newtonian fluid. The yield stress is 0-100 Pa after 120 seconds.
Was determined from the gradient of the shear stress. It should be noted that this parameter is highly dependent on the stress / time gradient, with steeper gradients resulting in lower yield stress. For this reason, the rheological parameters of such systems are generally measured under well-defined stress conditions.

In many cases, disrupted substructure rearrangement is combined with relaxation time. In such thixotropic systems, even the stress history of the system should be measured and examined for all rheological parameters. Therefore, 20 minutes before the measurement of the yield stress, the material is placed on the plate of the cone / plate measurement system. In the case of a single paste, the viscosity is measured by a creep test immediately after placing the material on the measuring system, and in the case of a mixed material, after 30 seconds.

In a vibration mode rotation / vibration rheometer (CS-50 Fa, Bohlin)
To measure the curing time t _c from the time the sweep. Measurements must be made under non-destructive conditions. This condition can be achieved by measuring within the linear viscoelastic range of both cured and uncured materials. The optimal conditions for the cure reaction of silicon addition cure are a frequency of 1 Hz and a strain of 0.001. When the shear modulus G ^* = G ′ + G ″ reaches a plateau, the cure time is read. Since this time is the same as the minimum removal time, the setting time is treatment related for the dentist.

The physical parameters of the examples of the invention (A, B and C) are shown in Table 3, along with three examples (C, E and D) not according to the invention.

[Table 7]

The large tear strength in Formulation F is due to the high filler content. Due to the high viscosity of both the single paste and the mixture, there is insufficient flow to obtain an optimal impression.

In Formula E, a low viscosity is obtained by dispersion of the filler. The flowability on the tooth surface is very good. The examples show that good wetting properties are obtained as a result of low contact angles. However, due to the very low tear strength, this formulation tears from the undercut.

In Example C, the flow properties and contact angles are optimized and the tear strength is as low as Formulation E, so that tearing from the undercut cannot be avoided.

The content of QM resin for reinforcement is not enough to improve the mechanical strength.

In Examples A, B and D according to the invention, both the single paste and the mixture have very low viscosities. When combined with a low contact angle, these rheological properties provide the paste with optimal fluidity on the tooth surface and in the sarcass. In Example C, a high mesh density was obtained, and in Example A, a high tear strength was obtained due to a high content of QM resin.

Table 4 shows the gel times t _g (uncured material) of the base paste according to the invention, measured by the time sweep described above.

[Table 8]

The base paste of Example C shows a very long gel time on a time sweep.
This formulation has a very weak rheological substructure that is inhibited under the measurement conditions (1.0 Hz, 0.0005 radians). It tends to separate under the influence of gravity. Therefore, there is no physical relevance in measuring thixotropic effects.

The minimum viscosity η ^* after inhibiting the rheological structure is important for the flow properties of the material, as well as the gel time. Only in the examples according to the invention (Examples A, B and D), a long gel time and a low viscosity are compatible.

[Brief description of the drawings]

FIG. 1 is a graph showing the wetting contact angle (degrees) as a function of time (minutes).

FIG. 2 is a graph showing the viscosity of an impression material as a function of time (minutes).

FIG. 3 is a graph showing the differences between the characteristics of the base and catalyst components of the present invention.

FIG. 4 is a graph showing the thixotropy of the base paste of the present invention measured using a vibrating rheometer and shown by time sweep.

FIG. 5 is a graph showing the change in viscosity during the curing reaction of the material of the present invention in a time sweep with an oscillating rheometer.

Claims (18)

[Claims] 1. A two-component polymerizable polyorganosiloxane composition for dental impressions, wherein one component comprises a polymerizing catalyst, the composition comprising: (a) a vinyl group-containing component; Having a viscosity of from 000 to about 7,000 mPa;
A first QM resin; (b) a second QM resin containing vinyl groups and having a viscosity of about 45,000 to about 60,000 mPa; (c) together with the QM resin about 0.16 to 0.24 mmole / g. (D) an organohydrogenpolysiloxane for crosslinking the vinyl groups, optionally, a linear vinyl-terminated polydimethylsiloxane liquid which forms a dispersion having a vinyl content; (e) to promote polymerization of the component. (F) silanized fumed silica; (g) a sufficient amount of a retarder component to temporarily delay the onset of the polymerization; (h) a filler; (i) an optional calcium sulfate; (J) an optional surfactant that imparts wettability to the composition, wherein the surface contact angle of the composition to water after 3 minutes is less than 50 °. In, the QM resin (a) consists of from about 15 to about 65 wt% of the dispersion, said 2QM resin (b) is a composition consisting of about 5 to about 45 wt% of the dispersion. 2. The dispersion of (a), (b) and (c) is about 5,000-60
The composition of claim 1 having a viscosity of 2,000 cps. 3. About 7 to about 10% by weight of said linear vinyl terminated poly (dimethyl).
The composition according to claim 1, comprising a siloxane liquid (d). 4. The composition of claim 1, comprising about 2.5 to about 10% by weight of the silanized fumed silica. 5. The composition of claim 1, wherein said filler comprises about 10 to about 45% by weight cristobalite and 0 to about 20% by weight diatomaceous earth, based on 100% by weight of the composition. 6. The dimethylvinylsilyl-terminated polydimethylsiloxane is present in an amount of from 0 to about 18% by weight and has the following chemical structural formula: The composition of claim 1, wherein n is an integer from about 50 to about 1300. Wherein said QM resin _{is, SiO 4/2} units and ^R 1 ^R _{2 2} Si
The composition of claim 1 comprising up to 4 units of O _1/2 , wherein R ¹ is an unsaturated group and R ² is an alkyl or aryl group. 8. The resin according to claim 1, wherein at least one of said QM resins (a) and (b) has the following formula: The composition according to claim 7, comprising: 9. The composition of claim 1 further comprising sufficient finely divided platinum metal to scavenge excess hydrogen gas generated during polymerization of the composition. 10. The composition of claim 1, wherein said retarder component is a low molecular weight vinyl-functional liquid that is a linear or cyclic polysiloxane in an amount of at least about 0.030% by weight of said composition. 11. The composition of claim 11, wherein the retarder component comprises about 0.030 of the composition.
The composition according to claim 10, comprising liquid 1,3-divinyldimethyldisiloxane in an amount of 〜0.10% by weight. 12. The method of claim 10, wherein said surfactant has an HLB of about 8-11 and a pLB of about 6-8.
2. The composition of claim 1 comprising H. 13. The surfactant according to claim 12, wherein the surfactant is a nonionic surfactant.
A composition as described. 14. The composition of claim 13, wherein said surfactant is nonylphenoxypoly (ethylenoxy) ethanol having an HLB of about 10.8. 15. After polymerization by chemical bonding, about 270 to 300 PSI (1.8
The composition of claim 1 having a tear strength of 6 to 2.07 MPa) and a water contact angle of less than 50 ° in 3 minutes. 16. A method for making a dental impression of oral hard and soft tissue in a humid environment, comprising mixing a two-component polymerizable polyorganosiloxane composition and containing a polymerized catalyst. One component that comprises: (a) containing vinyl groups and having a viscosity of about 5,000 to about 7,000 mPa;
(B) a second QM resin containing vinyl groups and having a viscosity of about 45,000 to about 60,000 mPa; (c) about 0.16 to 0.24 mmole / g with the QM resin; (D) an organohydrogenpolysiloxane for crosslinking the vinyl groups, optionally, a linear vinyl-terminated polydimethylsiloxane liquid to form a dispersion having a vinyl content; (e) to promote polymerization of the component. (F) silanized fumed silica; (g) a sufficient amount of a retarder component to temporarily delay the onset of the polymerization; (h) a filler; and (i) wetting the composition. An optional surfactant which imparts a property, wherein the surface contact angle of the composition to water after 3 minutes is less than 50 °, wherein the QM resin (a) is The second QM resin (b) consists of about 5 to about 45% by weight of the dispersion; placing the mixture in contact with tissue; curing the mixture to an impression Removing the impression from the tissue. 17. A dental impression produced by the method of claim 16. 18. The method of claim 16, wherein the surface contact angle of the composition to water is from about 2 minutes to less than about 50 ° from placing the impression to cure.