JP2751939B2 - Implant material and method for producing the same - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an implantable material such as an artificial bone and an artificial root, and a method for producing the implantable material.

2. Description of the Related Art Conventionally, a method has been employed in which a portion of a bone is excised due to a disease such as a malignant tumor or osteomyelitis, and then an artificial bone formed of metal or the like is substituted for the excised bone. Such an artificial bone, for example, after removing a part of the bone, providing a space for inserting the artificial bone into the remaining bone, then filling the void with a bonding agent, and then attaching the artificial bone Insert into the agent,
Next, the gap between the bone and the artificial bone was filled by curing the coalescing agent. Then, a peroxide as a catalyst and a polymerization initiator obtained by combining a peroxide and a tertiary amine are blended with the coalescent, and methyl methacrylate (hereinafter referred to as “MMA”) is added at room temperature. A method of polymerization and curing is employed.

However, the curing reaction of this MMA is an exothermic reaction, and when the reaction rate is high, the MMA (or the cured product) becomes high when the MMA is cured. Therefore, there is a high possibility that the bone tissue is changed by the heat of polymerization. The cured product of this MMA has low affinity for living organisms,
Since substantially no adhesive force is developed between the artificial bone and the hardened body and between the hardened body and the bone, there is a problem that loosening occurs at each boundary surface with the passage of time.

Under such circumstances, a method has been proposed in which the artificial bone itself and the bone have an affinity, and the bone grown over time is combined with the artificial bone surface to integrate the artificial bone and the bone. I have. In other words, by coating the surface of the artificial bone with calcium phosphate such as hydroxyapatite (hereinafter referred to as “HAP”) having a high affinity for bone, new bone that grows over time on the human body becomes calcium phosphate. Attempts have been made to absorb and integrate the bone to fix the artificial bone.

In this artificial bone, since calcium phosphate itself does not have an adhesive force with the artificial bone, it is important to adhere calcium phosphate to the artificial bone firmly and cover the artificial bone. Inadequate adhesion caused many problems.

That is, in order for the artificial bone or artificial tooth root coated with calcium phosphate to exhibit expected functions, calcium phosphate must be firmly adhered to the metal which is the skeleton of these structures. However, many implantable materials such as artificial bones and artificial roots coated with calcium phosphate do not satisfy such requirements. Furthermore, in order for calcium calcium phosphate to fully exhibit biocompatibility,
It has been said that it is necessary to coat the metal with calcium phosphate having a crystal structure equivalent to that of living hard tissue and high purity.

In order to satisfy these demands, it was necessary to produce a material for transplantation through a complicated process, and in this production, it was necessary to treat calcium phosphate at a high temperature. However, no implant material produced in this way is satisfactory in terms of biocompatibility.

The problem of the above-described artificial bone is not limited to the artificial bone, but also applies to implantable materials other than the artificial bone such as an artificial tooth root.

An object of the present invention is to solve the problems of the prior art as described above, and an object of the present invention is to provide an implantable material having excellent adhesion to bone.

SUMMARY OF THE INVENTION An implant material according to the present invention has a polyalkyl methacrylate derived from a methacrylate having an alkyl group having 1 to 4 carbon atoms, calcium phosphate such as HAP, and an alkyl group having 1 to 4 carbon atoms. Alkyl methacrylate, 4- (2-methacryloyloxyethyl) trimellitic anhydride (hereinafter, referred to as 4-META) and / or 4- (2-methacryloyloxyethyl) trimellitic acid obtained by hydrolyzing it (hereinafter, referred to as 4-META) , 4-
MET) and at least a portion of the metal surface is coated with a cured product of a composition comprising a polymerization initiator.

In addition, the above-mentioned method for producing a material for transplantation has a carbon number of 1
Polyalkyl methacrylate derived from methacrylate having an alkyl group of 4 to 4, calcium phosphate such as HAP, alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, 4-META and / or 4-META.
It is characterized in that at least a part of the metal surface is coated with a composition comprising MET and a polymerization initiator, and then the coated composition is cured.

The material for transplantation of the present invention has on its surface a layer composed of a specific cured polyalkyl methacrylate fat blended with calcium phosphate such as HAP. Since the calcium phosphate has a structure similar to that of the bone, the grown new bone absorbs and integrates the calcium phosphate.
In addition, since the specific polyalkyl methacrylate exhibits excellent adhesiveness to metal, even if the implantable material of the present invention is used for a long time as an artificial bone such as an artificial joint, there is a gap between the implantable material and the bone. Very little loosening occurs. Furthermore, the transplant material does not require a complicated manufacturing process, and can be easily manufactured at, for example, a temperature near normal temperature.

Next, the transplantation material of the present invention and the method for producing the same will be described in detail.

FIG. 1-a shows an example of a cross section of the artificial bone according to the present invention.

The artificial bone 1 according to the present invention includes a metal 2 and a coating layer 3 formed on at least a part of the surface of the metal 2 and formed of a cured body of polyalkyl methacrylate containing calcium phosphate.

In the artificial bone according to the present invention, the metal forming the artificial bone 1 is a metal which has no adverse effect on the living body even when used in the living body for a long time, and has a property which does not change for a long time. used. As such a metal, for example, stainless steel is used.

Such an artificial bone can be formed into various forms according to the site where the artificial bone is used. FIG. 1-a shows an artificial bone used as a hip joint, which can be used as an artificial joint forming a joint such as a knee joint, an ankle joint, or the like. It can be particularly effectively used for a portion to be adhered to bone-like tissue.

A hardened material layer 3 containing calcium phosphate is provided on the surface of the metal 2 of the artificial bone 1 according to the present invention.

The hardened body layer 3 is usually provided on the entire surface where the artificial bone 1 joins with the bone, but this layer 3 may be provided only on a part of the joint surface with the bone.

This layer 3 is made of a cured product of polyalkyl methacrylate containing calcium phosphate, and this cured product is formed of a cured product of a resin composition containing a base polymer, calcium phosphate, a monomer component and a polymerization initiator.

The polymer serving as the base of this cured product has 1 carbon atom.
It is a polyalkyl methacrylate having up to 4 alkyl groups.

Specific examples of such a base polymer include polymethyl methacrylate, polyethyl methacrylate,
Examples thereof include polypropyl methacrylate and polybutyl methacrylate, and copolymers having a repeating unit constituting the above polymer. Such a base polymer can be used alone,
They can be used in combination.

Among these base polymers, polymethyl methacrylate is particularly preferable as the base polymer because of its low harm to the human body (probability of causing harm to the human body).

As such a base polymer, a polyalkyl methacrylate having a polystyrene equivalent molecular weight determined by GPC of usually 10 ³ to 10 ⁸ , preferably 10 ³ to 10 ⁶ is used.

Such a polyalkyl methacrylate is preferably used in a powder state.

Since the calcium phosphate contained in the hardened material layer 3 has a composition relatively similar to that of the bone, the calcium phosphate is eventually integrated with the new bone as the bone grows, and is formed between the bone cement and the bone. Develop very high bonding strength.

Specific examples of the calcium phosphate used in the present invention include hydroxyapatite (HAP), fluorapatite, tricalcium phosphate, tetracalcium phosphate, and the like, and may be a mixture thereof with, for example, calcium oxide.

The calcium phosphate used in the present invention may be either heat-treated or non-heat-treated, and may be porous or dense.

In the present invention, calcium phosphate having various particle diameters can be used.In particular, by using calcium phosphate having an average particle diameter of 1 to 20 μm, the adhesive strength and compressive strength between the bone and the artificial bone are increased. Very high.
In particular, by using calcium phosphate having an average particle diameter of 2 to 15 μm, more preferably spherical calcium phosphate having the above average particle diameter, it is possible to form a cured body layer having further excellent adhesive strength and compressive strength. A composition can be obtained.

This calcium phosphate is preferably mixed with a polyalkyl methacrylate powder. In this case, the calcium phosphate and the polyalkyl methacrylate [component (P)] are mixed in a weight ratio, usually in the range of 0.1: 99.9 to 90:10, preferably in the range of 10:90 to 80:20. Used mixed.

In the present invention, at least two types of monomer components are used.

The first monomer component used in the present invention is an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms. Examples of such acrylic methacrylates include MMA, ethyl methacrylate, propyl methacrylate and butyl methacrylate. Among them, MMA is less harmful to the human body because of the polymer, and therefore, in the present invention, it is preferable to use MMA as a monomer component.

The second monomer component used in the present invention is 4-META and / or 4-MET having a structure represented by the following formula.

The above-mentioned mixture of alkyl methacrylate and 4-META and / or 4-MET is liquid in a normal use state, and apart from the above-mentioned polyalkyl methacrylate and calcium phosphate, 4-META is contained in a liquid methacrylate.
It is preferable to use 4-MET dissolved in advance.

In this case, the liquid component (L) is an alkyl methacrylate and 4-META and / or 4-MET, usually in a weight ratio in the range of 99.9: 0.1 to 85:15, preferably 99.
It is preferable to use a mixture in a weight ratio of 5: 0.5 to 90:10. By using 4-META and / or 4-MET and alkyl methacrylate in the above ratio, the adhesive strength of the composition and the strength of the cured product are particularly increased.

Further, the solid (powder) component (P) described above
And the liquid component (L), the component (P) / component (L) value is usually in the range of 0.01 to 10, preferably
It is blended so as to be contained in the range of 0.1 to 5.

As the polymerization initiator used in the present invention, use is made of a redox-based polymerization initiator combining a benzoyl peroxide and an amine generally used in producing an acrylic polymer at around room temperature, and alkylboron. In particular, tri-n-butylborane (hereinafter referred to as TB)
B) or a partial oxide thereof is preferably used. By using this TBB or its partial oxide, this compound reacts with oxygen or water in the atmosphere to generate radicals, and the radicals cause the alkyl methacrylate and 4-META and / or 4-META contained in the composition. -The polymerization reaction by MET proceeds, and the composition as described above is cured.

The polymerization initiator as described above causes a polymerization reaction,
It may be used in an amount sufficient for curing, and is used in a proportion of 0.1 to 1 part by weight based on 1 part by weight of the total weight of 4-META and / or 4-MET and alkyl methacrylate. In particular, when TBB is used, it is preferable to use TBB in a ratio of 0.3 to 0.4 parts by weight. The used amount of such TBB is larger than the used amount when used as a polymerization initiator of a dental adhesive composition, and used in such an amount, 4-ME
By using TA and / or 4-MET in combination with calcium phosphate, a good cured state can be realized, and properties such as adhesive strength and compressive strength between the layer 3 containing calcium phosphate and the metal 2 become particularly good.

In the composition for forming the cured body layer 3 as described above, each component can be prepared individually, and when used, these components can be mixed and used. It is advantageous to prepare the components separately and mix them immediately before use.

In this case, the solid component is obtained by mixing polyacryl methacrylate and calcium phosphate, which are base polymers. The solid component may contain an X-ray imaging agent such as barium sulfate, an antibiotic, or another filler. Further, it is preferable to use a sterilized solid component as described above. When a peroxide-based polymerization initiator such as benzoyl peroxide is used as the polymerization initiator, the polymerization initiator can be blended in the solid component.

The liquid component is 4-ME
Obtained by dissolving TA and / or 4-MET. The liquid component may contain a polymerization inhibitor such as hydroquinone in order to suppress the polymerization reaction of the monomer component during storage, and may further include an antibiotic, an X-ray imaging agent, and the like. Can also be blended. The curing reaction can be promoted by blending N, N-dimethyl-p-toluidine or the like into the liquid component.

The polymerization initiator is mixed in the solid component as described above or stored separately from the liquid component. Especially
When a polymerization initiator, such as TBB, which reacts with oxygen or moisture in the air to form a radical is used, it is generally sealed and stored in, for example, an ampoule or the like.

For example, by mixing the packaged composition with the solid component, the liquid component, and the polymerization initiator as described above, respectively, immediately before use, the curing reaction begins to proceed,
It can be used.

The composition according to the present invention is obtained by applying the composition containing calcium phosphate as described above to the surface of the metal 2 forming the artificial bone 1 or molding it in a Teflon mold or the like, and then curing the composition. Artificial bone can be manufactured.

The coating thickness of this composition can be appropriately set according to the use of the artificial bone, but the thickness of the cured body layer 3 is usually 0.1 μm or more, and preferably 1 to 500 μm. Applied or coated.

The composition applied in this way can be cured at room temperature or can be heated for curing.

Further, the shape of the covering portion can be easily deformed according to the shape and size of the cavity formed for embedding the artificial bone.

The artificial bone manufactured as described above can be bonded to the bone by using an adhesive (bone cement) having a composition equivalent to the composition used for forming the above-described hardened material layer 3. Alternatively, as in the case of a conventionally used artificial bone, it can be transplanted as it is and waited for bonding with the bone.

Since the calcium phosphate contained in the hardened material layer 3 has a structure similar to that of the bone, the new bone is finally integrated with the calcium phosphate, and the artificial bone adheres to the bone with a very strong adhesive force. In addition, there is no occurrence of looseness or the like in the bonded portion even after long-term use.

The artificial bone and the artificial tooth root of the present invention are, as described above, in addition to the metal and the hardened body of the specific composition coated with the metal, as well as the embodiment shown in FIG. 1-b. There may be.

That is, as shown in FIG. 1-b, the artificial bone according to the present invention includes a metal 22 and a calcium phosphate layer 24 provided on a surface of the metal 22 facing the bone. Here, as the metal 22, the same metal as that described above can be used.

The calcium phosphate layer 24 can be manufactured by using a known method such as a method of compression-molding calcium phosphate. That is, it can be manufactured by arranging calcium phosphate around the metal 22 so as to form a space into which the metal 22 can be inserted, and pressing and shaping the calcium phosphate, followed by sintering.

And the artificial bone 21 according to the present invention is
22 and calcium phosphate 24 are bonded using a polyalkylmethacrylate-based composition containing calcium phosphate as described above.

That is, as described above, the composition used herein is a polyalkyl methacrylate derived from a methacrylate having an alkyl group having 1 to 4 carbon atoms, calcium phosphate, and an alkyl group having 1 to 4 carbon atoms. An alkyl methacrylate having the composition, 4-META and / or 4-MET, and a polymerization initiator,
The metal 22 and the calcium phosphate layer 24 are adhered by the cured body 23 of this composition.

In this case, the thickness of the cured body 23 is usually 1 μm or more, preferably in the range of 1 to 500 μm. The thickness of the calcium phosphate layer 24 is usually in the range of 0.1 to 10 mm, preferably 0.1 to 5 mm.

Next, an example of a method for using the artificial bone and the like according to the present invention will be described.

FIG. 2 schematically shows an example of an artificial hip joint using the artificial bone according to the present invention.

First, a cavity 13 for inserting the artificial joint 12 into the femur 11
After forming the artificial bone of the present invention, the shape and size of the covering portion are adjusted according to the shape and size of the cavity 13.
Insert into 13. The calcium phosphate on the surface of the artificial joint 12 inserted in this manner has a structure very similar to the new bone, so that the calcium phosphate and the grown new bone are finally integrated. In this way, the femur and the artificial joint are also joined by the joining force resulting from the integration of the new bone and calcium phosphate, so that the femur does not easily become loose even during long-term use.

As described above, the present invention has been described using an artificial bone as an example, but the technique of the present invention can be applied to an artificial tooth root.

FIG. 3-a is a sectional view schematically showing an example of the artificial tooth root according to the present invention.

The artificial dental root 31 according to the present invention includes a metal 32 and a hardened material layer 33 of a polyalkyl methacrylate composition (the bone cement composition of the present invention) covering at least a part of the surface of the metal.

FIG. 3-b is a cross-sectional view schematically showing another example of the artificial tooth root according to the present invention.

As shown in FIG. 3-b, the artificial tooth root 41 according to the present invention
Is a metal 42 and a hardened material layer 43 of the bone cement composition of the present invention.
And a calcium phosphate layer 44 provided thereon so as to face the jaw bone.

As the metals 32 and 42, the same metals as those described above can be used. In addition, the respective cured body layers 33 and 43
The calcium phosphate layer 44 can also be formed in the same manner as described above.

An artificial tooth using the artificial tooth root according to the present invention can be implanted as follows.

After exposing the jawbone from toothless gums thereon, a cavity is formed in the jawbone for inserting an artificial root, and then the cavity is filled with the bone cement composition. Thereafter, an artificial root is inserted into the cavity filled with the bone cement composition, and the artificial root is fixed to the cavity by curing the bone cement composition.

As shown in FIG. 3-a and FIG. 3-b, a groove is formed in the axial direction substantially at the top of the artificial tooth root.

An artificial tooth is formed by screwing or adhering a protrusion formed on the bottom of the dental arch into the groove, and then covering the dental arch with a crown.

Table 1 shows an example of the compressive strength of the composition used in the present invention.

The compressive strength of the above composition is, for example, 93 g of polymethyl methacrylate (Acrybase, ME-3F, manufactured by Fujikura Kasei Co., Ltd.) mixed with 7 g of barium sulfate to prepare a polyalkyl methacrylate component. 0.8 g of powder and a porous spherical HAP (Ca / P) having an average particle size of 5 μm and 15 μm
= 1.67) 0.2 g are mixed to prepare a solid component (P) whose HAP content varies within the range of 20 to 80% by weight.

Separately, 19.0 g of MMA and 4-META and / or 4-MET1.0
g to prepare a liquid component, 0.4 g of this liquid component
Then, 3 drops (about 0.15 to 0.20 g) of TBB are added and mixed well, and then 1 g of the solid component (P) is blended and mixed to prepare a composition. × 4.0mm × 3.0mm
A cured body sample having a diameter of 6 mm and a length of 8 mm is prepared, and the former is immersed in water for two months, and the latter is measured for compressive strength using Autograph (DSS500, manufactured by Shimadzu Corporation). Can be obtained by Here, the compressive strength is the strength when the sample is broken.

Table 1 also shows the compressive strengths of cured samples of the compositions in which the HAP content in the solid component (P) prepared in the same manner as above was 40%, 60%, and 80%.

As a control, the measurement of the compressive strength of a cured product sample obtained from a composition containing no HAP is also shown.

As is clear from Table 1, when HAP is added, the compressive strength increases, and within the range of the present compounding ratio, the strength of the cured product tends to increase as the compounding ratio of HAP increases. This suggests that HAP has a role in improving the compressive strength of the cured product. Furthermore, since the affinity between the hardened bone cement and the bone is improved by increasing the blending amount of HAP, when the HAP is blended within the above-mentioned predetermined range, the adhesion between the bone and the hardened bone cement is improved. Strength can be maintained for a long time.

Table 2 shows an example of the adhesive strength when a human femur and an acrylic rod or stainless steel (sus-304) are adhered with the above composition.

For example, by attaching a masking tape,
An acrylic rod having a diameter of 5 mm is adhered to the exposed femur with an area of 22 cm ² using the above composition (leaving time: 30 minutes).

Next, this acrylic rod or stainless steel (sus-3
04) After immersing the attached femur in water for one day,
Using an autograph, the adhesive strength between the femur and the acrylic rod is measured at a crosshead speed of 2 mm / min.

In the above composition, when the 4-META concentration was changed to 3% by weight, 10% by weight, and 0% by weight with respect to the liquid component, and the adhesive strength was examined, the results shown in Table 3 below were obtained. .

4-META is extremely effective in bonding human femurs and stainless steel.
The effectiveness is particularly high in the range of ５5% by weight.

In addition, MMA and 4-MET from the cured product as described above
When the solubility of A is measured, for example, it is as follows.

That is, for example, the composition as described above is formed into a columnar shape (diameter 6 mm, length 8 mm) and cured, and then this columnar cured product is immersed in methanol for one week, and then the monomer eluted in methanol is dissolved. The amount of the body (MMA, 4-META) was measured, and the elution amount was determined by liquid chromatography (MATERS Micro Bordapac18;
(MeOH: H ₂ O = 7: 3, 1 ml / min) shows a tendency as shown in Table 4.

Further, even if HAP in the bone cement composition is changed to the following porous calcium phosphate, the compressive strength of the hardened body, for example, bone such as human femur and stainless steel (SUS-304)
A similar effect is exhibited in adhesive strength to metals such as.

a) Ca / P = 1.5 tricalcium phosphate heat treated at 950 ° C. for 4 hours b) Mixture of HAP and Ca / P = 1.60 HAP and tricalcium phosphate heat treated at 950 ° C. for 4 hours c) At 950 ° C. Mixture of HAP and calcium oxide with Ca / P = 1.75 heat treated for 4 hours.

Effects of the Invention The implantable material of the present invention has a layer made of a specific cured polyalkyl methacrylate compounded with calcium phosphate such as HAP on the surface. Since the calcium phosphate has a structure similar to that of bone, the grown new bone absorbs and integrates the calcium phosphate. In addition, since the specific polyalkyl methacrylate exhibits excellent adhesiveness to metal, even if the implantable material of the present invention is used for a long time as an artificial bone such as an artificial joint, there is a gap between the implantable material and the bone. Very little loosening occurs. Furthermore, the transplant material does not require a complicated manufacturing process, and can be easily manufactured at, for example, a temperature near normal temperature.

[Brief description of the drawings]

FIG. 1-a is a sectional view schematically showing an example of the artificial bone according to the present invention. Fig. 1-b is a cross-sectional view schematically showing another example of the artificial bone according to the present invention. 1,21 ... artificial bone 2,22 ... metal 3,23 ... composition hardened body 24 ... calcium phosphate layer Fig. 2 shows a hip joint formed by embedding the artificial bone according to the present invention in the femur. It is a figure which shows typically. 11 Femur 12 Metal 13 Cavity 14 Composition hardened body FIG. 3-a is a cross-sectional view schematically showing an example of the artificial tooth root according to the present invention. FIG. 3-b is a sectional view schematically showing another example of the artificial tooth root according to the present invention. 31,41 artificial dental root 32,42 metal 33,43 cured composition 44 calcium phosphate layer

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takashi Yamamoto 61-2, Waki, Waki-cho, Kuga-gun, Yamaguchi Prefecture Inside Mitsui Petrochemical Industry Co., Ltd.

Claims (9)

(57) [Claims] 1. A polyalkyl methacrylate derived from a methacrylate having an alkyl group having 1 to 4 carbon atoms, calcium phosphate, an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, and 4- (2-methacryloyl). (Oxyethyl) a transplant material, wherein at least a part of the metal surface is coated with a cured product of a composition comprising trimellitic acid and / or an anhydride thereof and a polymerization initiator. 2. The composition according to claim 1, wherein the composition comprises calcium phosphate and polyalkyl methacrylate.
Component (P) containing a weight ratio within the range of 1: 99.9 to 90:10 and alkyl methacrylate and 4- (2-methacryloyloxyethyl) trimellitic anhydride at 99.9: 0.1 to 85: 1.
Component (L) contained in the range of 5 in an amount such that the value of component (P) / component (L) is in the range of 0.01 to 10, and the amount of the polymerization initiator in the composition. Is in the range of 0.1 to 1 part by weight with respect to 1 part by weight of the component (L). 3. The polyalkyl methacrylate is a methacrylate homopolymer selected from the group consisting of methyl methacrylate, ethyl methacrylate, propyl methacrylate and butyl methacrylate or a copolymer thereof, and the alkyl methacrylate is methyl methacrylate. The material for transplantation according to claim 1, characterized in that: 4. The implant material according to claim 1, wherein the calcium phosphate is hydroxyapatite. 5. The implant material according to claim 1, wherein the calcium phosphate is sintered calcium phosphate. 6. An average particle size of calcium phosphate is 1 to 20 μm.
2. The implantable material according to claim 1, wherein the value is in the range of m. 7. The implant material according to claim 1, wherein the polymerization initiator is tri-n-butylborane. 8. A metal layer comprising a metal and a calcium phosphate layer provided on a surface facing the bone, wherein the metal and the calcium phosphate layer are derived from methacrylate having an alkyl group having 1 to 4 carbon atoms. Polyalkyl methacrylate, calcium phosphate, and 1 to 1 carbon atoms
An alkyl methacrylate having an alkyl group of 4;
-An implant material which is adhered with a cured product of a composition comprising (2-methacryloyloxyethyl) trimellitic acid and / or an anhydride thereof and a polymerization initiator. 9. A polyalkyl methacrylate derived from a methacrylate having an alkyl group having 1 to 4 carbon atoms, calcium phosphate, an alkyl methacrylate having an alkyl group having 1 to 4 carbon atoms, and 4- (2-methacryloyl). Transplantation characterized by coating at least a part of a metal surface with a composition comprising (oxyethyl) trimellitic acid and / or anhydride thereof and a polymerization initiator, and then curing the coated composition. Method of manufacturing materials.