JP2015083537A - Snap cure-prepared joint filler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a joint filler system for a cured type joint filler having an excellent storage life in a state of being prepared and a swift curing time after the addition of an activator.SOLUTION: Provided is a joint filler system including a curing inhibition, preliminary wetting, curing type prepared joint filler, and a curing initiator. The joint filler system includes aluminum alum crystals (such as the hydride of aluminum potassium sulfate 12), a calcium-free phosphate curing preventive, and a cured type joint filler base including the semi-hydrate of calcium sulfate. The semi-hydrate of calcium sulfate includes calcium carbonate of below 2 wt.%, the joint filler base does not include calcium carbonate other than the calcium carbonate included in the semi-hydrate of calcium sulfate, the amount of the alum is 0.5 to 2 g to 100 g of the joint filler system, and the alum is directly added and mixed to the joint filler system.

Description

  The present invention relates to a prepared joint material. In particular, the present invention relates to a joint material that is hardened immediately and reliably within a predetermined time.

  Walls made of gypsum wallboard are conventionally constructed by attaching wallboard panels to studs and filling and coating the joints between the panels with a specially formulated composition called joint material. A wet joint material (dry mold, taping grade) is placed in the joint formed by the adjacent edges of the wallboard panel, and the reinforcing paper tape is embedded in the joint together with the joint material and then dried. When the joint material is dried, a second joint material (overcoat or finish grade) is applied to the joint and also dried. A third application of the jointing material is usually required and may be lightly polished after drying, finished conventionally with decorative materials (paint, texture or wallpaper) and then applied to the wall. Instead of using two grades of joint material, universal joint materials are commercially available for both tape embedding and finish coating. When a fiberglass reinforcing tape is used, it is applied to the wall before the joint material is applied, and is used together with the chemical curing type joint material. For the taping process, the curable joint material is applied to the fiberglass tape and then penetrates the tape.

  Conventionally, all joint materials contain fillers, binders and thickeners. Taping grade joint materials generally contain more binder than topcoat grades. Conventional fillers are calcium carbonate, calcium sulfate dihydrate (gypsum) and calcium sulfate hemihydrate (baked gypsum). Calcium sulfate hemihydrate is used only for curable joint materials as disclosed in US Pat. No. 3,297,601. In current construction work, it is generally preferred to use a pre-wet and dry joint material containing either calcium carbonate or gypsum filler. Pre-mixed, pre-wet, dry type joints are a problem that mixes powdered material with water in the field of airborne dust, messy floors and work space, eliminates clumping to obtain a smooth mixture and extra time. This is preferable because of its simplicity of elimination. However, these conventional dry-type joint materials shrink during drying, making it more difficult to obtain a smooth wall surface, and each of the dry-type joint materials can be applied before an additional coat can be applied. Must be completely dry.

In order to avoid the disadvantages of dry type joint materials, curable type joint materials originally have low shrinkage and can be recoated after curing, making construction faster. Powder-cured joint materials have the disadvantage that they need to be drill mixed with water on-site when in use. In-situ drill mixes for powdered joints generate and scatter excessive dust, making it difficult to eliminate lumps to obtain a smooth mixture and require more time than using pre-prepared joints And
The prior art of US Pat. No. 5,746,822, incorporated herein by reference, discloses a pre-cured joint material. Anti-curing agents are useful for interrupting the chemical conversion of calcium sulfate hemihydrate to calcium sulfate dihydrate. The ability to interrupt the chemical curing process makes it possible to produce a curable joint material that is in a pre-prepared form rather than a powder. By using a curing inhibitor, the curing reaction interrupted in the prepared cured joint material can be restored upon addition of the curing activator. The advantages of the preferred pre-moistened product are thus incorporated into the product along with the advantages of shrink and recoat of the curable joint material. U.S. Pat. No. 5,746,822 comprises premixed cementitious components including wet calcium sulfate hemihydrate, conventional joint material binders and thickeners and hardeners for cementitious bases. Two-component compositions are described. Another component, a curing activator such as zinc sulfate, resumes the chemical curing reaction previously interrupted by the curing inhibitor. Zinc sulfate is a slow-acting curing initiator. Even when used in a relatively large amount, the joint material activated with zinc sulfate takes a long time to be sufficiently chemically hardened. The applicator must wait until the application of the subsequent coat until the joint material coat is sufficiently hardened and hardened, and possibly the next day.

  Alum is known as a calcium sulfate hemihydrate-based chemical hardening accelerator. It accelerates the curing hydration reaction in a mixture of calcined gypsum and water. However, alum is rarely used because it foams excessively due to the presence of calcium carbonate. Calcium carbonate can be present as a naturally occurring contaminant of other raw materials or as an added component. In joint materials, this type of foaming results in loss of strength and surface crater formation. Also, due to the dramatic volume expansion from foaming, the joint material may overflow and expand from the mixing container, and if the expansion continues after the joint material is applied to the wallboard surface, the finished joint will expand. This can lead to unsightly convex seam processing (crown seams). While the prior art teachings suggest avoiding the use of alum in stuccos containing calcium carbonate, they avoid suggesting any other solution to this problem.

  At least one of these benefits is realized by a joint material system that includes a cure-inhibited, pre-wet, and curable joint material formulated with an additive that can be delivered to the customer as a prepared joint material and a separate cure initiator Is done. The present invention combines the use of a potential curing initiator with a pre-wet, curable joint material made without calcium carbonate to provide a rapid and strong curing action without excessive foaming. is there.

  A cure-inhibited, pre-wet, and curable joint material comprises a pre-set cured joint base and a calcium-free phosphate hardener that prevents chemical hydration of the gypsum component of the cured joint material. Including. The joint material base does not contain calcium carbonate. The curing initiator includes alum to resume the chemical hydration reaction.

  Surprisingly, it has been found that alum can be used as a curing initiator without excessive foaming, together with a pre-cured joint material with added curing inhibitor. The joint material system uses a combination of calcium-free phosphate hardener, alum as a hardener and a limited amount of calcium carbonate in the joint base. This combination of features provides long-lasting cure prevention and provides a smooth and creamy texture without compounded functionality, immediate cure on addition of alum cure initiator, and excessive foaming of joint material. give.

  The ability to use alum as a curing initiator that does not cause excessive foaming problems provides several advantages. The degree of hardening and hardening is much faster and stronger with alum curing initiators compared to prior art zinc compounds. This allows for “snap-curing”, where the joint material is quickly cured and can be re-coated or polished immediately after application to the wall or ceiling panel. This composition further has the advantage that a substantially foam-free joint material can be produced while providing the desired snap-curing performance not available in the prior art. Alum also uses much less curing activator than when using prior art zinc sulfate, allowing the curing activator to be more easily incorporated into a pre-wet, cured base. By reducing the amount used, the weight and amount of curing activator required in the field can be significantly reduced and the curing initiator can be sold in a less bulky concentrated form.

  Joint material systems have been developed for curable joint materials that have excellent shelf life in the prepared state and a rapid cure time after addition of an activator. The system includes a cure-inhibited, pre-wet, cure-type joint material and a separate portion of alum added when using the joint material system.

  Curing-suppressed, pre-wet, and curable type joints are pre-prepared, curable type joint bases in which the cement-based curing reaction is inactivated, prevented or stopped. One major component of the pre-wet, curable joint material is a long-term cure inhibitor that maintains a pre-prepared hydraulic base. The presence of water will normally hydrate the calcium sulfate hemihydrate within 0.1 to 5 hours at a cure time controlled by the delayed additive. Additives that have been found to provide long-term hardening prevention effects in formulated cementitious compositions are phosphates that do not contain calcium. In particular, (1) zinc hexametaphosphate and (2) potassium tripolyphosphate have been shown to provide long-term cure prevention effects, and (3) tetrasodium pyrophosphate provides the longest lasting cure prevention effect. Other effective anti-curing agents include (4) sodium tripolyphosphate, (5) monoammonium phosphate and (6) potassium dihydrogen phosphate. Usually, the anti-hardening effect is obtained with low levels of phosphate additives in amounts ranging from about 0.1 to about 2% by weight, based on the total weight of the composition excluding water. In certain embodiments, the phosphate additive is present in an amount of about 0.1 to about 0.6%, based on the total weight of the composition excluding water. The phosphate curing inhibitor is optionally a water-soluble salt of phosphoric acid, excluding the calcium salt of phosphoric acid. As used herein, the term “calcium-free phosphate hardener” reliably excludes the calcium salt of the anti-hardening joint material.

  Phosphate cure inhibitors are used in place of or in addition to conventional cure retarding additives. An example of a useful cure retarder is a protein retarder such as a SUMA cure retarder. Certain embodiments based on joint materials use between about 0.02% and 1% retarder, while in some embodiments, between 0.02% and. 1% is used. The retarders are used in any useful amount, alone or in combination with each other. The addition of a conventional cure retarder has little effect on long-term cure prevention as obtained with phosphates that do not contain calcium, but when the hydration reaction is resumed using a cure initiator, the conventional cure retarder Helps to control the curing time of the prepared cured joint material.

  The other main component of the joint base is a gypsum component such as calcium sulfate hemihydrate filler. The alpha crystalline form of calcium sulfate hemihydrate has been found to be preferred for long-term maintenance of uncured formulated compositions containing calcium-free phosphate. Generally, at least about 20 weight percent (20%) of the dry joint base is calcium sulfate hemihydrate, up to about 99 weight percent (99%) of the dry ingredients, more preferably 60% to about 90%. Range. Other forms of calcium sulfate hemihydrate including the beta crystal form and / or mixtures of alpha and beta forms are also useful.

  Calcium carbonate is known to exist in powdered gypsum, a newly mined source of calcium sulfate. Calcium carbonate is often present in calcium sulfate hemihydrate as a contaminant. For many applications, calcium carbonate is an inert filler and is not problematic. However, adverse effects including excessive foaming have been observed when calcium carbonate and water combine with alum. To use a joint base with an alum activator, it is important that the calcium sulfate hemihydrate is substantially free of calcium carbonate. Calcium sulfate hemihydrate “substantially free” of calcium carbonate means that the hemihydrate contains less than 2% by weight of calcium carbonate. Certain embodiments of calcium sulfate hemihydrate include less than 1%, and even less than 0.5% calcium carbonate. In at least one embodiment, the calcium sulfate hemihydrate does not include calcium carbonate.

  When calcium carbonate is not in the joint base, in some embodiments, an inert filler is optionally used as a swelling agent. A preferred inert filler is talc. Because it is approximately the same density as calcium carbonate, calcium carbonate can be replaced by an equal amount of talc, resulting in a slight change in the density of the joint base. While other fillers may be used, the relative amounts of other components in the joint base may also need to be adjusted to maintain the desired joint density.

  When producing a joint base, other conventional joint material components may be incorporated into the composition. Latex emulsion binders are an important component well known to those skilled in the joint material industry. Any conventional latex binder may be used, with polyvinyl acetate and ethylene vinyl acetate emulsions being preferred. When present, the latex binder ranges from about 0.5% to about 15% by weight of the composition prior to the addition of water, and in some embodiments, 1% to about 8% is used. The use of spray-dried binders is also conceivable.

  It is generally preferred that the joint base includes one or more thickeners. Conventional cellulose thickeners such as ethyl hydroxyethyl cellulose, hydroxypropyl methyl cellulose, methyl hydroxypropyl cellulose, hydroxyethyl cellulose and mixtures thereof may be used for the joint material of the present invention. The amount of cellulose thickener, if present, ranges from about 0.1% to about 3%, preferably 0.3 to 1% by weight of the total composition component without added water. Good. It is contemplated that other thickeners may be used instead of or in addition to the cellulose thickener.

  The joint base of the present invention may also contain a non-leveling agent such as attapulgus clay. This component provides non-leveling, slipping and water retention. Attapar gas clay has been found to provide a joint material having good working properties, and the use of attapulg clay is described in U.S. Pat. No. 3,297,601 in a pre-set cured joint material. Assists in the long-term suspension and stability of In general, the amount of non-leveling agent, if present, ranges from about 1% to about 10%, preferably 2% to 7% by weight of the base composition before adding water. Other clays such as sepiolite, bentonite and montmorillonite may also be used for the joint base in addition to or instead of clay.

  Conventional blended joint materials often contain fillers such as diatomaceous earth, mica, talc, or sericite to provide crack resistance when dry. These ingredients can be omitted from the joint base of the present invention, which has good crack resistance, without mica and talc, but a small amount of mica is required during formulation to provide improved slip and workability. Or it may be desirable to include talc. When used in the joint base of the present invention, the mica or talc may be from about 2% to about 15% by weight of the composition before adding water.

  The jointing material of the present invention preferably has a pH in the range of 7-8. In some cases, it may be necessary to use an additive such as citric acid to lower the pH. In general, the pH control additive may be present in an amount ranging from 0.1 to 1% by weight of the joint material composition.

  It is conceivable to use additional components commonly used in joint materials in the joint material system of the present invention. These ingredients, optionally including but not limited to, humectants, fillers, wetting agents, kaolin, antifoaming agents and plasticizers are also useful in the joint bases of the present invention.

  If a lightweight formulated joint material is desired, light weight properties can be provided by incorporating expanded perlite into the joint material base in accordance with the disclosure of US Pat. No. 4,454,267. It is well known in the industry that expanded pearlite should preferably have a particle size that will pass through a 100 mesh screen if it is to be incorporated into a joint base. In the formulated joint material, the expanded perlite is optionally treated to be insensitive to water or left uncoated. When it is advantageous to treat expanded perlite, there are several ways to make the expanded perlite insensitive to water, one of which is disclosed in US Pat. No. 4,525,388. Has been. Another method is to treat expanded perlite with a silicone or siloxane compound, but other materials may be used to make it insensitive to water (ie, water repellency). Specially treated expanded perlite is commercially available from suppliers such as Silbrico Corporation.

  In order to achieve the desired light weight properties, the expanded perlite must be present in an amount of at least about 3% by weight of the total components in the formulated cementitious joint material, excluding water. It is particularly preferred that the expanded perlite is present in an amount of from about 5% to about 10% by weight of the total components in the joint material excluding water.

  Water is added in an amount selected to produce a joint material of the desired viscosity. Certain embodiments of the invention are directed to Brabender viscosities of 200 to 400 Brabender units. The measurement is based on using a type A probe and a 250 cmg torque head.

  When preparing a formulated joint material, it is necessary to control the growth of microorganisms in the wet medium during storage. One way to reduce microorganisms is by introducing a biocide that shocks the joint base and kills by contact. Examples of contact biocides include household bleach (6% aqueous sodium hypochlorite) or shock treatment chemicals for swimming pools such as lithium or calcium hypochlorite. These additives will kill substantially all microorganisms present in the joint base during manufacture, but they will not prevent subsequent microbial growth.

  Conventional canned preservatives such as MERGAL 174 and / or FUNGITROL 158 are used for continuous inhibition of microbial growth. They can be used in combination with or instead of contact killing. Combinations of preservatives are also conceivable.

  The second component of the joint material system is alum. This component serves to activate the pre-wet, curable type joint material, to resume the calcium sulfate hemihydrate / water hydration reaction and to chemically cure the joint material. “Alum” means any aluminum sulfate, including aluminum disulfate, potassium and aluminum sulfate double salts, and aluminum and ammonia sulfate double salts. A hydrated form of alum is also conceivable. The amount of active agent used can be reduced using alum. Alum is used in an amount of about 0.5 grams to about 2 grams, based on 100 grams of formulated joint material.

  The blended cementitious composition of the present invention can function as a curable type joint material when a curing activator is added in order to start a curing action at the time of use. Accelerators can avoid the effects of phosphate hardeners and can hydrate, chemically harden and harden calcium sulfate hemihydrate. After adding the curing initiator to the wet blend joint material, a hydration reaction takes place (calcium sulfate hemihydrate becomes calcium sulfate dihydrate), and the hard-cured article is formed in minutes or hours. Manufactured.

Example 1
Using the ingredients in Table 1, a pre-wet, cure-inhibited, curable type joint material was produced. No. One shock agent refers to a dry calcium hypochlorite shock agent commonly used in swimming pools. Bleach refers to a household bleach that is an approximately 6% aqueous solution of sodium hypochlorite. Both bleach and pool shock are used as contact biocides.

In Table 1 above, “Methocel”, “Suma”, “Mergal” and “Fungitrol” are registered trademarks, and “Hubercarb”, “Talcron”, “Silbrico”, “Celvol” and “Halltech” are unregistered trademarks.
For both of the above compositions, the joint base was prepared by weighing the dry ingredients and mixing them in a container. The dry ingredients included calcium sulfate hemihydrate, calcium carbonate or talc, perlite, thickener and retardant.

  Water was weighed and placed in a second container. For this example, the target Brabender viscosity was 250. The remaining wet ingredients were also weighed and added to the water. The wetting component included a latex emulsion and a preservative.

  The wet and dry ingredients were mixed to form a prepared joint material. The curing of the joint material was subsequently suppressed until the amount of alum shown in Table 1 was added.

  The joint material was tested for cure time. The data is shown in Table 2. Vicat cure time refers to ASTM C-472, incorporated herein by reference. Vicat curing time was started when alum was added to the prepared joint material. A 100 gram sample of prepared joint material was mixed with a predetermined amount of alum. The sample was poured onto an acrylic sheet to form a putty. A 300 gram Vicat needle was placed perpendicular to the putty surface, halfway between the center and outer edges of the putty. The needle was held on the putty surface, released, and allowed to fall freely with its own weight. The curing time when the needle could not penetrate to the bottom of the putty was determined.

  The recoat cure time was the time until the joint material solidified enough to withstand the deformation during the recoat. As the curable joint material hydrates and the reaction proceeds, the temperature rises. Higher temperatures reflect faster cure times.

  Comparing the conventional joint material and the joint material of the present invention, it can be seen that the joint material of the present invention can obtain a faster curing time even when the same curing initiation compound, that is, alum, is used. This is confirmed by the recoat curing time, Vicat curing time and Vicat temperature.

  Furthermore, an improved product is obtained which is smooth and creamy during mixing. During mixing, there is no foaming and there is no expansion of the product.

  While specific embodiments of formulated joint materials have been shown and described, those skilled in the art will recognize that changes and modifications may be made in its broader correspondence without departing from the invention. I will.

[Appendix 1]
With alum,
A calcium phosphate-free phosphate curing agent;
water and,
A joint material system comprising a curable joint material base comprising calcium sulfate hemihydrate, wherein the joint material base has no additional calcium carbonate, and the calcium sulfate hemihydrate comprises about 2 A joint material system containing less than weight percent calcium carbonate.
[Appendix 2]
The joint material system according to claim 1, wherein the calcium sulfate hemihydrate is less than 0.5% calcium carbonate by weight of the calcium sulfate hemihydrate.
[Appendix 3]
The joint material system according to supplementary note 1, wherein the calcium sulfate hemihydrate does not substantially contain calcium carbonate.
[Appendix 4]
The joint material system of claim 1, wherein the base further comprises a latex emulsion binder present in an amount ranging from about 1% to about 15% by weight of the base composition before adding water.
[Appendix 5]
Item 5. The appendix of claim 4, wherein the latex emulsion binder comprises one of a compound selected from the group of emulsions or spray-dried powders consisting of polyvinyl acetate, polyvinyl alcohol, ethylene vinyl acetate, styrene acrylic, styrene butadiene, and mixtures thereof. Joint material system.
[Appendix 6]
The joint material system of claim 1, wherein the base further comprises a non-leveling agent present in a range of about 1% to about 10% by weight of the base composition prior to the addition of water.
[Appendix 7]
The joint material system according to supplementary note 6, wherein the non-leveling agent is selected from the group consisting of leptite, bentonite, montmorillonite, attapulgus clay, and a mixture thereof.
[Appendix 8]
The joint material system according to appendix 1, wherein the calcium-free phosphate curing inhibitor, the water, and the curable joint base are premixed to form a cured, pre-wet, and curable joint material. .
[Appendix 9]
A hardened joint base comprising alum, calcium-free phosphate hardener, calcium sulfate hemihydrate, and water;
A joint material wherein the joint material base has no additional calcium carbonate and the calcium sulfate hemihydrate comprises less than about 2% by weight calcium carbonate.
[Appendix 10]
A cure-suppressed, pre-wet, cure-type joint material base comprising calcium sulfate hemihydrate, water, and a calcium-free phosphate cure inhibitor, having no additional calcium carbonate, Obtaining said joint material base wherein calcium sulfate hemihydrate comprises less than about 2% by weight of calcium carbonate;
Packaging the cure-inhibited, pre-wet, and cured joint base together with a separate piece of alum;
A method for producing a joint material, comprising blending the curing-suppressing, pre-wetting and curing-type joint base and the alum.

Claims (10)

Alm,
A calcium phosphate-free phosphate curing agent;
water and,
A curable joint base containing calcium sulfate hemihydrate;
A joint material system including
The calcium sulfate hemihydrate comprises less than 2 wt% calcium carbonate;
The joint base has no calcium carbonate other than the calcium carbonate contained in the calcium sulfate hemihydrate,
The alum is in an amount of 0.5 to 2 grams per 100 grams of the joint material system,
The alum is added and mixed directly into the joint material system,
Joint material system.   The joint material system according to claim 1, wherein the calcium sulfate hemihydrate includes less than 0.5% of the calcium carbonate per weight of the calcium sulfate hemihydrate.   The joint material system according to claim 1, wherein the calcium sulfate hemihydrate does not contain the calcium carbonate.   The joint material system of claim 1, wherein the joint material base further comprises a latex emulsion binder present in an amount ranging from 1% to 15% by weight per weight of the joint material base prior to the addition of water.   The latex emulsion binder is one of the compounds selected from the group consisting of polyvinyl acetate, polyvinyl alcohol, ethylene vinyl acetate, styrene acrylic, styrene butadiene, and mixtures thereof, and takes the form of an emulsion or spray dried powder. The joint material system according to claim 4, comprising:   The joint material system of claim 1, wherein the joint material base further comprises a non-leveling agent present in a range of 1% to 10% by weight of the composition of the joint material base prior to the addition of water.   The joint material system according to claim 6, wherein the non-leveling agent is selected from the group consisting of leptite, bentonite, montmorillonite, attapulgous clay, and mixtures thereof.   The joint material system according to claim 1, wherein the calcium-free phosphate hardening inhibitor, the water, and the joint material base are premixed to form a cure-suppressed, pre-wet, and curable joint material. A hardened joint base comprising alum, calcium-free phosphate hardener, calcium sulfate hemihydrate, and water;
The calcium sulfate hemihydrate comprises less than 2 wt% calcium carbonate;
The joint base has no calcium carbonate other than the calcium carbonate contained in the calcium sulfate hemihydrate,
The alum is in an amount of 0.5 to 2 grams per 100 grams of joint material,
The alum is added and mixed directly into the joint material.
Joint material. A cure-suppressed, pre-wet, and curable joint base comprising calcium sulfate hemihydrate, water, and a calcium-free phosphate curing inhibitor, wherein the calcium sulfate hemihydrate is 2 The joint material base contains less than wt% calcium carbonate, and the joint material base has no calcium carbonate other than the calcium carbonate contained in the calcium sulfate hemihydrate, and obtains a joint material base.
Packaging the joint base with a separate piece of alum;
Blending the joint base and the alum;
The said alum is a manufacturing method of the joint material used for 0.5-2 grams with respect to 100 grams of joint material.